Despite all the achievements of modern medicine, the percentage of postoperative complications remains at a fairly high level. Based on numerous studies, we can conclude that many methods of managing patients in the perioperative period are ineffective, for example, fasting before surgery, prolonged preoperative bowel preparation, routine use of nasogastric tubes and drainage of postoperative wounds, and prolonged bed rest.

In search of a solution to the problem of reducing the number of postoperative complications and accelerating the rehabilitation of patients in the postoperative period at the end of the 90s in the 20th century, the Danish anesthesiologist-resuscitator Professor N. Kehlet proposed a multimodal program, the main goal of which was to reduce the body’s stress response to surgery, patients after planned surgical interventions.

This program is called “Fast-Track Surgery”. The concept of “Fast-track” covers all phases of perioperative therapy: preoperative, intraoperative and postoperative. Growing interest in this program is reflected in abdominal surgery, oncology, gynecology, urology and other surgical disciplines.

  • Preoperative patient information.
  • Refusal of mechanical bowel preparation before surgery.
  • Refusal of preoperative fasting of the patient and the use of special carbohydrate mixtures 2 hours before surgery.
  • Refusal of premedication.
  • Prevention of thromboembolic complications.
  • Antibiotic prophylaxis.
  • Minimum surgical access and minimally invasive surgery.
  • Adequate volume of infusion during surgery.
  • Regional anesthesia and short-acting analgesics.
  • Refusal of routine abdominal drainage.
  • Intraoperative normothermia.
  • Effective pain relief in the postoperative period.
  • Prevention of nausea and vomiting. Early enteral nutrition.
  • Early mobilization. (Wind J., 2006).

The “Fast-track” program does not have clear boundaries and strictly defined points; it is a dynamically developing concept. In its development, the use of new techniques, approaches to treatment, the use of new pharmacological agents, and updating the arsenal of diagnostic and treatment equipment play an important role.

Nowadays, there is an active development of new components such as blood-saving technologies, targeted infusion therapy, prevention of cognitive disorders in the perioperative period, which require additional study.

Preoperative period

Patient information

At the preoperative stage, the surgeon and the anesthesiologist-resuscitator talk with the patient. The task of doctors is to explain to the patient their treatment plan. It is important to focus on the role of the patient himself: explain the importance of early activation after surgery, the importance of early enteral nutrition, and breathing exercises.

It has been proven that detailed information information about surgical intervention and anesthesia, a description of what will happen to them in the perioperative period, helps reduce fear and anxiety, and shorten the length of hospital stay.

As part of the “Fast-track” program, an anesthesiologist-resuscitator plays an important role in the treatment of the patient. The main task of which is the preoperative assessment of the patient’s condition, preparing the patient for surgical intervention, which consists in correcting existing disorders associated with the main and concomitant pathology.

Avoiding mechanical bowel preparation

For many years, mechanical preparation before surgery was considered a routine procedure. This was justified by the hypothesis that bowel cleansing will reduce bacterial contamination of the intestine, and this in turn will reduce the number of postoperative complications (abscess, peritonitis, intestinal anastomotic leakage, wound infection) during operations involving opening of its lumen.

Contrary to traditional ideas, this type of preparation leads to dehydration and prolonged postoperative paresis of the gastrointestinal tract. Preparation with enemas has no advantages and, in particular, in terms of the frequency of anastomotic leaks, wound infections and other complications, the need for subsequent surgery.

A 2012 meta-analysis including 13 randomized trials (5373 patients) found that mechanical bowel preparation did not reduce postoperative complications, including anastomotic leak, total wound infection, extra-abdominal septic complications, reoperation, or death. .

It has also been shown that mechanical preparation has no effect on reducing the incidence of complications after cystectomy using segments of the small intestine for urine diversion. To date, a number of European surgical associations have excluded mechanical bowel preparation from their recommendations for elective abdominal surgery.

Refusal of preoperative fasting of the patient

Long-term fasting was a routine method of preparing a patient for surgery. The basis for this was the theoretical assumption that refusal to eat reduces the risk of aspiration of gastric contents.

This hypothesis was first questioned back in 1986. In 2003, M. S. Brady et al. published a meta-analysis of 22 randomized trials of preoperative fasting. The results showed that stopping all fluids 2 hours before surgery did not increase the incidence of aspiration complications in elective surgery compared with that in patients fasting from midnight before surgery. There were also no differences in the amount of gastric contents and its pH level.

It is now known that preoperative fasting reduces glycogen reserves and causes postoperative insulin resistance. In the early postoperative period, in response to surgical aggression, there is a significant release of a large number of stress hormones, such as adrenaline, norepinephrine, cortisol, glucagon, catecholamines, as well as a large number of inflammatory mediators (cytokines). As a result, the effect of insulin decreases and insulin resistance develops.

Using the principles of evidence-based medicine, it has been demonstrated that preoperative fasting reduces glycogen reserves and causes postoperative insulin resistance. As a result, it is justified to use 150 ml of dextrose (glucose) 2 hours before surgery, which also helps reduce feelings of hunger, thirst, discomfort, fatigue, and, consequently, the stress response. In addition, carbohydrate therapy reduced nitrogen losses in the postoperative period and prevented the development of insulin resistance.

Refusal of premedication

One of the conditions for implementing the “Fast-track” surgery program is the refusal of premedication with a change in the intraoperative anesthesia regimen. Premedication is effective for correcting the psycho-emotional status, but does not correspond to the concept of “Fast-track” surgery, as it increases the patient’s awakening time after completion of the surgical intervention.

The traditional pain management regimen, including premedication based on a narcotic analgesic, may cause excessive sedation in the postoperative period, which is considered a significant factor in the development of postoperative cognitive dysfunction, which unpredictably prolongs the rehabilitation period of surgical patients. To reduce the total dose of narcotic analgesics, these drugs are excluded from premedication.

Prevention of thromboembolic complications

In the clinical practice of a doctor of any specialty, especially surgery, timely diagnosis, treatment and, of course, prevention of deep vein thrombosis (DVT) and PE are extremely important.

Venous thromboembolic complications (VTE) is a collective concept that combines saphenous and deep vein thrombosis, as well as pulmonary embolism (PE). The frequency of deep vein thrombosis and pulmonary embolism in modern conditions, taking into account the preventive measures taken, varies, according to various sources, from 0 to 6.4%, while in large series this frequency does not exceed 1%.

In surgical patients, the source of pulmonary embolism in more than 90% of cases is thrombosis in the inferior vena cava system. On average, their frequency is 1 in 1000. More than 30% of cases of pulmonary embolism and deep vein thrombosis are directly related to general surgical interventions; in orthopedic operations, their frequency is already about 50%.

It is known that extensive surgical interventions, like any other type of injury, involve the mechanism of a systemic inflammatory response, which consists in the production and release of a large amount of biologically active substances into the blood. A cascade of cytokines activates leukocytes and promotes their adhesion to the vascular endothelium. Powerful oxidants released by activated leukocytes cause the death of endothelial cells with subsequent exposure of the subendothelial layer.

In addition, thrombus formation is facilitated by the release of tissue thromboplastin into the bloodstream directly during tissue excision, which significantly activates the coagulation system, and long-term immobilization of patients in the postoperative period, promoting blood stasis in the venous bed.

Prevention of thromboembolic complications in patients at increased risk of thrombus formation is widely used in surgical practice and includes elastic compression of the lower extremities and the use of low molecular weight heparins. Numerous studies have proven the effectiveness of pharmacological prevention of VTEC using unfractionated heparin (UFH) and low molecular weight heparin (LMWH). A study of 4195 colorectal surgery patients demonstrated that pharmacological prophylaxis reduced the incidence of VTEC from 1.8% to 1.1%, as well as overall mortality from colorectal cancer.

Antibiotic prophylaxis

Of course, one of the most important criteria for early rehabilitation of patients is the absence of septic complications in the postoperative period. According to the Russian multicenter study ERGINI, surgical site infections (SSI) account for about 15% of all nosocomial infections developing in hospitals emergency assistance Russian Federation.

Infections of the surgical site have a great impact on the duration of hospitalization of patients; when they occur, the length of the patient's stay in the hospital significantly increases to 16.7 days and the cost of hospitalization increases.

Microbial contamination of a surgical wound is inevitable even with ideal adherence to the rules of asepsis and antisepsis. By the end of the operation, in 80-90% of cases, the wounds are contaminated with various microflora, most often Staphylococcus aureus, KNS, Enterococcus spp. and Escherichia coli..

In studies that examined the quantitative content of microorganisms in tissues in the surgical area, it was shown that when contamination exceeds 105 microorganisms per 1 g of tissue, the risk of RI increases significantly. In addition, the properties of microorganisms are important: their ability to cause invasion, produce toxins (typical of gram-negative microorganisms), and attach and survive in host tissues (typical of gram-positive microorganisms).

In order to prevent purulent complications in the postoperative period, antibacterial drugs are used. Many studies have shown that a short course of prophylaxis that begins shortly before the skin incision is as effective as a long course (over 24 hours or more). The spectrum of activity of prescribed antibiotics should include aerobic and anaerobic bacteria.

In studies of the effectiveness of various types of skin treatment, it was found that the overall incidence of postoperative wound infections was 40% lower in the group that used a concentrated alcohol solution of chlorhexidine than in the group that used povidone-iodine. However, there is a risk of injury and thermal burns if diathermy is used in the presence of alcohol-based skin solutions.

Intraoperative period

Regional anesthesia and short-acting analgesics

“Balanced anesthesia/analgesia” is a central element of the program for accelerated recovery of the patient after surgical interventions. Today it has already become known that the need for the use of long-acting anesthetics is somewhat overestimated and is accompanied by a delay in recovery due to inadequate fluid intake and late activation of the patient in the postoperative period.

The introduction into clinical practice of rapidly and short-acting volatile (sevoflurane) and intravenous (propofol) anesthetics, opioids (remifentanil) and muscle relaxants has expanded the indications for operations performed on an outpatient basis, shortened the duration of the recovery period, and reduced the need for long-term monitoring. Preference is given to short-acting drugs - propofol, midazolam and remifentanil - which make anesthesia more manageable and reduce recovery time after anesthesia.

The use of regional epidural and spinal anesthesia is accompanied by improved lung function, reduced stress on the cardiovascular system, less intestinal paresis and better analgesia.

The conscious use of regional anesthesia allows not only to effectively block pain impulses, but also to a certain extent to neutralize the pathophysiological changes caused by surgery. It has also been proven to reduce the risk and incidence of thromboembolic and respiratory complications, myocardial infarction, renal failure, as well as the need for blood transfusions and the incidence of infectious complications.

It has been proven that postoperative ileus is closely associated with pain, activation of the sympathetic nervous system caused by surgery, blockade of afferent pain signals and efferent sympathetic reflex arcs with intra- and postoperative epidural anesthesia minimizes the impact of the surgical stress response on intestinal function, accelerates the resumption of peristalsis, thereby ensuring early passage of gas and stool.

In abdominal surgery, blockade of nociceptive stimuli and efferent sympathetic reactions minimizes the impact of surgical aggression on the intestine, which helps accelerate the resumption of peristalsis. A catheter installed before surgery can be used for prolonged epidural analgesia with continuous administration of drugs through a special pump.

Epidural anesthesia has been shown to reduce the need for postoperative opioid use, which in turn may affect the incidence of postoperative nausea and vomiting. Epidural anesthesia allows segmental anesthesia (for example, only the mid-thoracic segments) and is the optimal method of postoperative pain relief (in the presence of an epidural catheter). Such anesthesia can be carried out in the postoperative period for several days (on average three days).

In a study by V. M. Muehling et al. in the group of patients in whom epidural analgesia was used as one of the components of the “Fast-track” protocol during lung resection, a decrease in the incidence of pulmonary complications was observed from 35 to 6.6%. In addition, with a high degree of evidence, the superiority of epidural analgesia compared with opioid analgesia in the postoperative period during open surgery in relation to pain correction has been established; prolonged epidural analgesia was better in reducing pain after 6, 24 and 72 hours than patient-controlled opioid analgesia (mean difference (MD) 1.74, 95% CI (1.30-2.19), 0.99, 95% CI (0.65-1.33), and 0.63, 95% CI (0.24- 1.01), respectively, reducing the incidence of postoperative nausea and vomiting, as well as pneumonia (OR) 0.54; 95% CI (0.43-0.68) regardless of the level of epidural catheter installation).

Nowadays, there is a revival of interest in inhalation anesthesia (IA), which has long been most widespread in the world. The first drug for AI registered in the Russian Federation was sevoflurane. In our country, considerable experience has been accumulated in the use of this anesthetic and a large number of works have been published. The recognized advantages of modern IA include good controllability and safety, rapid onset of effect and cessation of the anesthetic effect, and dosage accuracy based on the minimum alveolar concentration (MAC). The depth of anesthesia is varied by turning the vaporizer knob on the anesthesia machine, and the MAC serves as a reproducible depth reference.

A promising method is also catheterization of the surgical wound with the introduction of a solution of local anesthetics for postoperative pain relief, which makes it possible to transfer patients to specialized departments. However, the presence of a catheter in the epidural space or postoperative wound limits mobility and slows down the rehabilitation of patients, having a negative impact on the timing of Fast-Track support for surgical patients.

Minimum surgical access and minimally invasive surgery

Of course, the volume of surgery plays a large role in the process of rehabilitation of patients in the postoperative period. But the choice of operational access is also important. Pain and pulmonary dysfunction have been shown to be less common when transverse or oblique incisions are used instead of a long vertical laparotomy incision, presumably due to fewer dermatomes being involved.

Nowadays we are witnessing the rise of the era of endoscopic surgery. Minimally invasive surgery is characterized by less pain, a relatively low risk of complications, and shorter hospital stay. Today, there is reliable data on the possibility of performing laparoscopic operations for diseases that most often cause peritonitis: acute appendicitis, acute destructive cholecystitis, pancreatic necrosis, perforated gastric ulcers and DNA.

Also, a smaller amount of damage to the peritoneum during laparoscopy reduces the number of adhesive postoperative complications, and minimal surgical trauma contributes to the early restoration of all body functions, especially small intestinal motility. Whereas laparotomy, in turn, is a rather traumatic intervention, and in turn can aggravate stress disorders, loss of protein and electrolytes, suppress immune defense mechanisms in the postoperative period, and cause a number of serious complications.

However, the use of laparoscopic access, despite minimal trauma to the anterior abdominal wall, does not relieve patients from postoperative pain. The cause of pain in the postoperative period during laparoscopic operations is irritation of the peritoneum by carbonic acid formed during the hydration of carbon dioxide used in carboxyperitoneum.

In patients operated on in the absence of gas insufflation using an isopneumatic regimen using laparolifting, there is practically no postoperative pain, or it is mild. According to L. Lindgren et al., only 8% of patients operated on using gasless laparoscopy complained of postoperative shoulder pain - compared to 46% of those operated on using pneumoperitoneum.

However, the pain caused by laparoscopic surgery is less severe than that caused by laparotomy. Randomized studies have demonstrated the effectiveness of laparoscopic surgery compared with open access when using accelerated rehabilitation protocols.

Adequate volume of infusion during surgery

The main goal of intraoperative fluid therapy is to maintain normal stroke volume and hemodynamics to ensure normal perfusion of tissues and organs. The basis of this approach is active infusion therapy, as well as the early use of sympathomimetics and pressor amines.

Uncontrolled infusion therapy at the intraoperative stage can lead to hyper- and hypovolemia. It is also known that uncontrolled use of pressor amines due to vasoconstriction can lead to anastomotic failure in abdominal surgery. The amount of infusion required cannot be determined in advance as a fixed volume of solutions; it must be individual for each patient.

Hypervolemia, caused by absolute or relative excess of volemic load, contributes to increased capillary permeability and the development of tissue edema, which can serve as the basis for the emergence of a vicious circle of capillary leakage. It has been proven that hypervolemia can lead to iatrogenic edema.

Under conditions of hypovolemia, the risk of developing various complications in the postoperative period also increases. The intestinal mucosa is constantly regenerating, has a high degree of metabolic activity and is thus extremely vulnerable to ischemia. In addition, surgical trauma itself triggers a cascade of pathophysiological reactions, which in turn lead to an increase in capillary permeability and causes the release of a liquid particle of blood outside the vascular bed. An imbalance in favor of crystalloid solutions and their use in a volume of 5 ml/kg doubles the edema.

In connection with this, the concept of targeted therapy (GNT) is becoming increasingly widespread, allowing individualization of the prescription of solutions and vasoactive drugs based on algorithms for assessing various hemodynamic variables. It has been established that CNT makes it possible to optimize the state of the intravascular sector, thereby maintaining tissue perfusion and oxygenation at the proper level, helping to improve outcomes after major surgical interventions.

Intraoperative normothermia

Compliance with intraoperative normothermia as one of the elements of the “Fast-track” program is intended to help prevent a number of complications in the early postoperative period. A decrease in temperature of 1-2 °C during surgery can lead to peripheral vasoconstriction and a decrease in oxygen delivery to tissues.

The development of intraoperative hypothermia entails a number of pathological reactions, resulting in deterioration of hemostasis with an increase in intra- and postoperative blood loss, increased postoperative tremors with increased oxygen consumption and an increased risk of myocardial ischemia.

In particular, a decrease in temperature has a negative effect on the blood coagulation system (increased blood viscosity, prolongation of clotting time, thrombocytopenia), the immune system (immunosuppression associated with impaired phagocytosis, activation of the complement system, production of cytokines and antibodies), the cardiovascular system (decreased cardiac output, vasodilation, increased release of catecholamines). It has been proven that ensuring normothermia and preventing tremors lead to a decrease in the number of cardiovascular and infectious complications, an increase in hemodilution tolerance and a faster recovery after general anesthesia. Warming patients before surgery also has a positive effect on temperature maintenance.

Postoperative period

Effective pain relief

A key element of the concept of accelerated recovery is adequate pain relief in the postoperative period. It is pain that is the main irritating element of surgical treatment. The optimal analgesia regimen after major surgery should provide a sufficient level of pain relief, promote early mobilization, more active restoration of bowel function and nutrition, and not cause complications.

It is pain that is the main subjective factor slowing down the process of accelerated rehabilitation of patients. Postoperative pain itself represents only the visible part of the iceberg, being the root cause of the development of a pathological postoperative symptom complex.

Postoperative pain not only causes the patient’s psycho-emotional discomfort, but also stimulates the activity of the sympathoadrenal system, which under certain conditions negatively affects vital organ functions and triggers the formation of chronic postoperative pain syndrome. It has been established that the course of the postoperative period and long-term results of surgical treatment are determined by the quality of pain relief.

Quite often, narcotic analgesics are used to relieve pain in the early postoperative period. However, their effective analgesic dose is often close to the dose at which respiratory depression, sedation, gastrointestinal paresis, and urinary and biliary tract dysfunction develop. Opioids also have a pronounced emetogenic effect, increasing the frequency of episodes of nausea and vomiting in the postoperative period, while the severity of the emetogenic effect is directly proportional to the administered dose. This negatively affects the condition of patients in the postoperative period, complicates their activation, and contributes to the development of respiratory and thromboembolic complications.

One of the most promising and effective pathogenetic agents for blocking peripheral pain receptors (nociceptors) are nonsteroidal anti-inflammatory drugs (NSAIDs). Today, the classic regimen of analgesia in the postoperative period, within the framework of the Fast-track program, includes a combination of opioids, NSAIDs and paracetamol. The prescription of NSAIDs in multimodal pain relief regimens is justified and effective, especially in terms of preventing opioid aftereffects.

The mechanism of action of NSAIDs is associated with inhibition of cyclooxygenase (COX) 1 and 2, suppression of prostaglandin synthesis, which results in pronounced analgesic, antipyretic and anti-inflammatory effects. Along with the central analgesic effect of NSAIDs, their peripheral effect is also noted, associated with an antiexudative effect, which leads to a decrease in the accumulation of pain mediators and a decrease in mechanical pressure on pain receptors in tissues.

The use of drugs in this group can reduce the incidence of postoperative nausea and vomiting, reduce the degree of sedation, and provide early mobilization and enteral nutrition.

Preventing nausea and vomiting

The problem of postoperative nausea and vomiting occurs in 25-35% of all surgical patients and is the main reason for patient dissatisfaction with treatment; in addition, due to this complication, discharge from the hospital is often delayed.

Today, the prevention of nausea and vomiting consists of prescribing corticosteroids, antiemetics, serotonin agonists and avoiding narcotic analgesics in the postoperative period. The introduction of dexamethasone in a dose of 4-8 mg into the premedication regimen and the use of ondansetron in a dose of 4-8 mg at the final stage of anesthesia can reduce the incidence of this unpleasant and unsafe complication.

Epidural anesthesia and transversus abdominis block have been shown to reduce the need for postoperative opioid use, which in turn may affect the incidence of PONV. In addition to improving well-being, effective prevention of nausea and vomiting promotes early initiation of enteral nutrition and restoration of intestinal motility.

Early enteral nutrition

Traditionally, the introduction of patients into the postoperative period involves the absence of enteral nutrition and intravenous infusions for 4-5 days. Numerous studies have proven that replacement parenteral nutrition is accompanied by an increase in septic complications.

In seriously ill patients in the postoperative period, conditions often arise that result in centralization of blood circulation. As a result, adequate perfusion and oxygenation of the gastrointestinal tract is disrupted. This leads to damage to intestinal epithelial cells with disruption of barrier function. Degenerative changes in the intestinal wall occur after just a few days of rest, and they progress despite adequate parenteral nutrition in full.

The disorders are aggravated if there are no nutrients in the lumen of the gastrointestinal tract for a long time, since the cells of the mucous membrane receive nutrition to a large extent directly from the chyme. It has been proven that complete functional rest of the intestine leads to atrophy of its mucous membrane.

The intestinal mucosa also serves as a protective barrier, isolating pathogenic microorganisms located in its cavity from the circulating blood. If this barrier is destroyed, pathogenic microorganisms can invade the mucous membrane, gaining access to the vessels. This process is called translocation. The latter may be the most important cause of latent sepsis in seriously ill patients; it is regarded as the first step towards multiple organ failure syndrome.

In turn, a balanced and correctly selected EN helps to reduce the severity of the body’s stress response and hypercatabolism, and more quickly restore the basic functions of the intestine. Early introduction of nutrients into the intestine helps maintain the functional and structural integrity of the intestinal epithelium, the synthesis of IgA by lymphoid tissue, and reduce bacterial translocation; the number of infectious complications is reduced.

There is also evidence that the direct penetration of nutrients into the intestinal lumen leads to increased metabolic processes and improved blood circulation, which results in a more rapid restoration of the functional state of the intestinal wall, normalization of protein metabolism and strengthening of the immune system.

Early enteral nutrition allows you to shorten the recovery time of intestinal functions and limit the volume of intravenous infusion, which also reduces the risk of postoperative complications.

Early mobilization

The last but not least important component of an accelerated recovery program is early mobilization. Prolonged stay in bed, in addition to subjective problems of perception of the treatment process and decline in well-being, increases the frequency of thromboembolic complications, respiratory disorders, reduces muscle strength and increases the risk of hemodynamic disorders.

It has been proven that early mobilization and muscle training can improve respiratory function and tissue oxygenation, reduce muscle weakness, and reduce the risk of deep vein thrombosis and pulmonary embolism.

Activation of the patient according to the “Fast-track” protocol begins immediately after the resumption of orientation in one’s own personality, space and time, restoration of the ability to perform active movements of the body and limbs, provided that the pain syndrome is at a level of 0-3 points on the visual analogue scale and there are no signs of breathing problems and blood circulation.

Conclusion

Promising initial results obtained with the Fast-tcrack program raise the need to change the established traditional system of management of patients with surgical pathology in order to improve postoperative outcomes. The “Fast-track” surgery program requires further study of each of the existing elements, as well as the development and introduction of new elements into practice.

Basnaev U. I., Mikhailichenko V. Yu., Karakursakov I. E.

It's no secret that MikroTik produces Software-Baser routers and the CPU takes care of most of the traffic processing. This approach has an advantage, because You can program almost any functionality and maintain a relatively unified system for all devices. But in terms of speed, they will always lag behind routers with specialized chips.


Software processing of packages has a number of disadvantages:

  1. Lack of wire speed - the processor (especially single-core) cannot work faster than specialized chips.
  2. Locks. With really large volumes of traffic (for example, DoS/DDoS), you may not be able to connect to the router even through the console interface, because all processor time will be occupied by traffic processing.
  3. Difficulty scaling. You cannot add a module that increases the speed of packet processing in hardware.

Developers are using various hardware and software solutions to improve the situation:

  1. The switch chip on inexpensive models allows you to process Layer2 traffic bypassing the CPU.
  2. SoC with a good network chip (CCR line).
  3. Using hardware encryption
  4. Various technologies that reduce the number of software processing for packages (FastPath and FastTrack), these will be discussed.

SlowPath vs FastPath

SlowPath is the basic traffic path through the internal subsystems of MikroTik, it can be quite varied and the longer the path, the higher the load on the CPU and the more the speed drops.


FastPath - algorithms that allow you to transmit traffic bypassing fairly large processing blocks.

Operating conditions and support on devices

Most modern routers and boards from MikroTik support FastPath, but there is a detailed list on the wiki:


Model Support on ethernet interfaces
RB6xx series ether1,2
Most of the RB7xx series all Ethernet ports
RB800 ether1,2
RB9xx series all Ethernet ports
RB1000 all Ethernet ports
RB1100 series ether1-11
RB2011 series all Ethernet ports
RB3011 series all Ethernet ports
CRS series routers all Ethernet ports
CCR series routers all Ethernet ports
Other devices Not supported

And a separate list for interfaces other than ethernet:



For FastPath to function fully, it requires support from both the incoming and outgoing interfaces. Only hardware queues should be enabled on interfaces.



And lastly, FastPath really doesn't like fragmented traffic. If the packet is fragmented, it will definitely get stuck on the CPU.

FastPath and Bridge

Bridge is a software interface used to create Layer2 communications between multiple hardware (or software) interfaces. If you combine 4 ethernet interfaces into a bridge on a router (and enable hw=yes) and one wireless, then traffic between the ethernet interfaces will go bypassing the software interface, and traffic between ethernet and wireless will use the software bridge. On routers with several chips (for example RB2011), traffic between interfaces from different chips will use the capabilities of the software bridge (sometimes, to reduce the load, interfaces are simply combined with a patch cord and in general this works).


FatsPath - applies only to traffic coming through the CPU (software bridge), usually this is traffic between interfaces from different chips, or the hw=yes option is disabled.


On Packet Flow, traffic passing through the Bridge looks like this:



And more details:



Included in the bridge settings (the setting is the same for all bridge interfaces) ->->, you can also see the counters there.



For FastPath to work in Bridge, the following conditions must be met:

  1. There is no vlan configuration on bridge interfaces (I think this is not relevant for the CRS series, where vlans are configured at the hardware level, but I could be wrong)
  2. There are no rules in /interface bridge filter and /interface bridge nat, these are the same blocks from the second circuit that the frame goes through.
  3. IP firewall is not enabled (use-ip-firwall=no). A good function for capturing traffic and debugging a network, but it is rarely turned on on an ongoing basis.
  4. Don't use mesh and metarouter
  5. The following are not running on the interface: sniffer, torch and traffic generator.

FastPath and Tunnel

In two words: a tunnel interface is the encapsulation of some packets into the load part of other packets. If you follow PacketFlow, then the red lines mark the original packet, the blue lines indicate the original packet encapsulated in a tunnel protocol packet (for example, ipip or gre; eoip gets into (and comes from) the bridging decision; with tunnel ipsec it’s still more interesting, but has nothing to do with fastpath).



Tunnel traffic in FastPath will not be visible in: firewall, queues, hotspot, vrf, ip accounting. But some packets will continue to be transmitted via SlowPath; this must be taken into account when configuring the Firewall.


For FastPath to work on tunnel interfaces, the following conditions must be met:

  1. Don't use ipsec encryption
  2. Avoid packet fragmentation (properly configure mtu)
  3. Enable allow-fast-path=yes on the tunnel interface

FastPath and Layer3

Layer3 is the transfer of packets between subnets; the router builds routing tables and, based on them, forwards the packet to the next hop.


On Packet Flow, network layer transit traffic looks like this:



let's go deeper



and even deeper



For FastPath to work on Layer3, the following conditions must be met:

  1. Do not add rules to the firewall (at all, even nat).
  2. Do not add entries to Address Lists.
  3. Do not configure Simple Queues and Queues Tree for parent=global , or interfaces on which you plan to get a working FastPath .
  4. Disable Connection tracker. The auto option was introduced specifically for FastPath to work in the absence of rules in the firewall.
  5. Don't use /ip accounting .
  6. Don't use /ip route vrf .
  7. Do not configure /ip hotspot .
  8. Don't add ipsec policies.
  9. Route Cache must be enabled.
  10. Running sniffer, torch and traffic generator interfere with the operation of FastPath.

It is enabled in the ip settings: ->, there you can also see counters of successfully processed packets.



Screenshot from home router. I have a fairly loaded firewall, several always-on L2TP/IPSec connections and queues. You can't even dream about FastPath.

FastTrack

IP packet marking technology for fast passage through Packet Flow.


For FastTrack to work, the following conditions must be met:

  1. Route Cache and FastPath must be enabled and active.
  2. Correct traffic marking configuration.
  3. Works only for UDP and TCP traffic.
  4. Do not use mesh and metarouter.
  5. Do not actively use: /tool ​​mac-scan and /tool ​​ip-scan .
  6. Running sniffer, torch and traffic generator interfere with the operation of FastTrack.

Traffic marked as fasttrack will not be processed in:

  1. Firewall filter (although this is debatable, I’ll show you why in an example);
  2. Firewall mangle;
  3. IPSec;
  4. Queues with parrent=global;
  5. Hotspot;

If something interferes with the passage of a packet along the fasttrack, it will be transmitted along the slow path along with all remaining packets.


Enabled by adding a rule (see below) to the Firewall. FastTrack only marks packets from an established connection (you can also mark new, but then there will be problems with NAT). The filter table is used because when marking fasttrack in prerouting, problems with NAT will again arise.

Synthetic test


FastPath Connection Tracker NAT FastTrack Speed CPU
- - - - ~932Mb/sec 100%(networking, ethernet)
+ - - - ~923Mb/sec 65-75%(networking, ethernet, unclassified)
+ + - - ~680Mb/sec
+ + + - ~393Mb/sec 100%(networking, firewall, ethernet)
+ + + + ~911Mb/sec 60-80%(networking, ethernet, unclassified)

And (for the last test) what was configured and how it worked:
Filtering rules continued to process traffic (if you disable allowing for established, related traffic went to drop), postrouting+mangle caught packets that did not get into FastTrack.





In Connection Tracker you can track FastTrack connections using the flag of the same name.



In Counters -> you can see that FastTrack is active and working, but FastPath is not.



/ip firewall filter add action=fasttrack-connection chain=forward connection-state=established,related add action=accept chain=forward connection-state=established,related add action=accept chain=forward connection-state=new add action=drop chain=forward /ip firewall mangle add action=mark-packet chain=postrouting connection-state=established,related new-packet-mark=q1 passthrough=no src-address=20.20.20.0/24 /ip firewall nat add action=masquerade chain=srcnat out-interface=ether1

Instead of a conclusion

To use or not?

  • FastPath for Bridge - Definitely yes. At least it reduces the load on the CPU.
  • FastPath for Tunnels - No. It works poorly and turns off if there is encryption.
  • FastPath for Layer3 - Debatably, most of the router's capabilities are lost. In a large network, closed from the wild Internet, it can have its own (small) gain.
  • FastPath for MPLS/VLAN/Bonding/VRRP - Enabled automatically if possible. There is no separate option for management.
  • FastTrack - Suitable for home and SOHO configurations without queues and a paranoid firewall. Synthetic tests with one client look good, in practice you need to very carefully monitor the traffic that leaked past FastTrack and look for the reason.

An exclusive service that allows you to go through all the formalities at the airport, such as registration, special control, without wasting time and in comfort, in the presence of an airport employee. passport control, boarding a plane.

Upon arrival You will be met at the jet bridge and taken through passport control to the VIP lounge, where your luggage will be delivered. A customs officer will approach you to complete the paperwork. You will be informed about the delivery of transport.

If the VIP service is booked less than 24 hours in advance, the cost of the service increases by 25%.

Ensuring fast passage of all airport formalities fast track at Barcelona airport from 23.00 to 7.00, as well as holidays assumes an increase in the cost of the service by 25%. Sunday + 10%. Payment in cash or card.

Upon departure You can also use this service. We need to agree on the meeting place in advance.

The service includes:

meeting at the airport,

quick registration, special control and passport control,

Fast track is an ideal solution for passengers who value their time. This service involves completing all formalities (registration for a flight, customs and passport control) in an expedited manner and without queues, accompanied by an airport representative. This service is very popular among frequent travelers and families with small children. Fast track service on this moment not implemented at all airports. Where this service is not provided, you can take advantage of the possibilities of VIP rooms, which often involve going through all the necessary procedures in the room and without queuing.

Cost of Fast track service at airports

  • Pulkovo from 7500 rub.
  • Zhukovsky from 6500 rub.
  • Türkiye
    • Antalya from 130 euros,
    • Istanbul from 165 euros,
  • Paris from 120 euros,
  • Milan from 170 euros,
  • Rome from 170 euros,
  • Bangkok from 135 euros,
  • Shanghai from 210 euros,

– these are just a few of the cities where we provide fast track service. You can order a VIP hall, which includes going through formalities in the hall without queuing.

What does the Fast track service include upon departure?

Having prepared to leave for the airport, the passenger contacts the assistant and agrees with him on the time of the meeting, which takes place at the check-in counters. Having arrived at the airport, an employee meets the passenger and accompanies him through all the necessary formalities (depending on whether he is on an international flight or domestic flight passenger arrives). Thus, the passenger undergoes all procedures in the common hall, but without queues and in an accelerated manner. After passing all security checks, the assistant leaves the passenger in the duty-free area, or, at the guest’s request, escorts him to the boarding gate.

What does the Fast track service include upon arrival?

The meeting of the arriving passenger and the airport employee takes place either at the exit of the plane or before passport control. Then, together, they go through passport control, avoiding the queue and, as a result, in an expedited manner. The assistant also assists in retrieving the passenger's luggage and accompanies the guest to the airport exit.

Fast track service for children

As a rule, children from 2 to 12 years old are served with a 50% discount, and children under 2 years old are served free of charge.
Group and family rates are popular at many international airports. 2 children under 12 years old can count as 1 adult.

Advantages of ordering Fast track service from Travelmart