Types of routes are the main indicators of routing. Network routing. Planning routing of cargo transportation
Lecture 19 Brief description of protocols
Questions:
1. Routing. Types and algorithms of routing.
2. Dynamic routing protocol RIP.
3. ICMP Control Message Protocol.
4. UDP protocol.
5. TCP protocol.
6. DNS protocol.
7. SNMP network management protocol.
8. Remote control protocols. Telnet protocol.
9. File exchange protocols.
10. SMTP, POP3, IMAP protocol.
11. HTTP protocol.
Routing refers to the movement of information from a source to a destination through an internetwork. Routing is often contrasted with bridging, which, in the popular understanding of this method, performs exactly the same functions. The main difference between the two is that bridging occurs at Layer 2 of the ISO reference model, while routing occurs at Layer 3. This difference accounts for the fact that routers use logical addresses (such as IP addresses) and bridges are hardware addresses.
From a commercial point of view, routing only gained popularity in the 1970s.
A routing table is a form of rules that sends IP datagrams from a given computer to the datagram's destination address. Routing tables are created not only in special devices - routers, but also on each computer. The routing table can be static or dynamic.
The distribution of static routing tables is set by the network administrator before routing begins. It does not change unless the network administrator changes it. Algorithms that use static routes are easy to develop and work well in environments where network traffic is relatively predictable and the network design is relatively simple.
Dynamic routing algorithms adapt to changing network conditions in real time. They do this by analyzing incoming routing update messages. If the message indicates that there has been a network change, the routing programs recalculate the routes and send new routing adjustment messages. Such messages permeate the network, prompting routers to re-run their algorithms and change routing tables accordingly.
Algorithm for searching a route in a routing table
The table contains entries that consist of a network address field, a network mask field, a gateway address field, a network interface address field, and a metrics field.
When a computer sends a datagram, it first determines whether the recipient's address is on the same branch as the sender's address, if so, then the datagram is sent to the recipient directly. (direct routing) If not, then the routing table is looked up for an entry corresponding to the address destinations (indirect routing).
The search algorithm is as follows. If for any record the bitwise product of the destination IP address and the network mask field coincides with the value of the network address field, then this datagram will be sent to the gateway corresponding to this record, specified in the gateway address field, through the network interface - the host of the datagram sender to this gateway , specified in the network interface address field.
In the TCP/IP stack, not only routers, but also end nodes make decisions about who to send a packet to for its successful delivery to the destination node, based on the so-called routing tables.
Consider the following example of organizing a small class C network connected to an Internet provider through a router, which at the same time provides communication between these two segments. Let the network number allocated to this organization be 210.20.30, and the Internet gateway address be 210.20.30.254.
Routing is the subject of a contract for the organization of cargo transportation by rail, therefore only the parties to the contract have the right to determine its content. It may provide for dispatch routes formed on a railway access track or at a railway station, groups of cars for organizing stepped station or section routes, etc. The originating route means a train composition of a specified weight or length, formed by the shipper on the railway access track of the organization or under an agreement with the railway at the railway station with the mandatory exemption of at least one technical station from processing such a train, provided for by the current plan for the formation of freight trains. Departure routes pass through one or more sorting stations without processing, therefore, the delivery of cargo is accelerated, the work on reforming trains is reduced, the cost of transportation is reduced, the turnover of wagons is accelerated, the need for wagons is reduced, the safety of transported goods is better ensured, and the competitiveness of manufacturers of goods and railway transport increases. Stepped routes are formed from wagons loaded by different shippers on the tracks of one or several stations of a section or junction. The rules for the transportation of goods along consignor routes by rail provide that in order to speed up the delivery of goods, reduce transport and operating costs, the transportation of goods can be carried out by consignor routes and be provided for in contracts for the organization of cargo transportation by rail. Sender routing is the basis for creating a network of logistics centers for Russian railways in the future.
Types of routing from loading points
Routing shipments from loading points is a highly efficient way to organize freight transportation. The procedure for transporting goods on shipping routes is established by the Rules for the transportation of goods on dispatch routes by rail. Depending on the destination, departure routes are:: – straight- when transporting to one destination (transshipment) station to one or more consignees (freight cars addressed to each consignee must be in a separate group); – into spray- when transporting by appointment to disbanding stations according to the plan for the formation of freight trains, or by appointment to route distribution points (stations) announced by the Ministry of Railways of Russia, where wagons are addressed (indicating destination stations and consignee) at unloading stations to specific consignees, or by appointment to entry and distribution stations receiving fuel cargo, with further redirection of wagons to unloading stations. The shipper agrees with the consignee on the possibility of accepting routes of a specified weight or length for unloading. If there is a change in the mass of the train (breaking point) in the direction of the station routes in the direction of reduction, the departure of the routes is organized from the core and the trailer part, which follows as part of the route to the turning point of the mass. Core- this is the main part of the sending route of the established mass, which follows without reorganization to the destination railway station in the event of a change in the mass of the train along the route. According to the conditions of circulation, sending routes are distinguished: – ring with constant composition which, after unloading, return in the same composition to the same station or department for re-loading; – ring with variable composition which, after unloading, return to the same station or department, while the number, type of cars and their purpose are retained, but if necessary, some cars can be replaced by other similar cars.
Organization of circular routes significantly reduces the cost of preparing cars for loading, while reducing downtime of cars at loading points, since cars require minimal preparation for loading.
Planning routing of cargo transportation
Transportation routing, a system for organizing the dispatch of goods by routes (as a whole train) from one or more railway stations with destinations at unloading points located in the same area. It is carried out according to routing plans drawn up by the railways. Routes are divided into: departure organized from wagons loaded by one sender at one station (pier or port); stepped- from wagons loaded by different consignors at one or more stations of one or two sections; formed at specialized route bases, which are created at the exits of mass loading areas . Based on travel distance, departure and step routes are divided into: local(intraroad) - when traveling within the same railway, and network- when traveling within two or more railways. Routes provided with a permanently assigned train of cars for circulation between specific points of departure and destination, are called ring. When planning and routing freight flows, it is important to consider the performance of vehicles depending on the transportation line. In other words, the allocated vehicles must ensure cargo flows along the developed travel routes. In transport logistics, models of problems of this type are formed depending on the degree of detail in taking into account the requirements for the functioning of various modes of transport.
38. Key indicators of implementation of the transportation routing plan
To analyze and evaluate the implementation of transportation routing tasks, the following main indicators have been established: 1) the number of wagons sent during the reporting period on routes in general and by type of cargo on average per day; 2) routing level (routing percentage) by type of cargo - determined by the ratio of the number of wagons loaded and sent on routes U mrsh, to the total number of loaded wagons U total, in percentage: 3) the average travel distance of all routes and wagons in their trains and by type of cargo: , where is the sum of route kilometers; - total number of routes; 4) distribution of cars sent on routes by distance belts and their percentage in the total number of loaded cars (range zones: up to 400 km, from 401 to 1000 km, from 1001 to 1500 km and over 1500 km); 5) the number of wagons sent on direct routes in general and by type of cargo and their percentage in the total number of loaded wagons; 6) average composition of routes (in cars) - determined by dividing the number of routed cars by the number of routes sent; 7) fulfillment of a task for the transportation of goods by routes - the ratio of the number of cars sent on routes and provided for by the task (in percentage).
To analyze and evaluate the performance of a routing task, the carrier sets the following key indicators:
1. number of vaginas. send for the reporting period in general and by type of cargo on average per day;
2. level of routing (%) for stations separately and the network as a whole and by type of cargo, determined by the ratio. number of wagons, loaded and send in routes to the total number of passengers. wagons in %. : φ m =u mrsh /u total *100;
3. average travel distance of all routes and cars in their trains and by type of cargo: l m = ∑N mrsh *l/N mrsh;
∑N mrsh *l – sum of route-km;
N mrsh – total number of routes;
3. distribution of wagons, departure. in routes along distance belts and their % in the total number of loaded cars;
range belts: up to 400 km; 401-1000km; 1001-1500km; over 1500km
4. number of wagons, departure. in direct routes and their % in the total number of loads. carriages;
5. The average composition of the route is determined by dividing the number of routed cars by the number of routes sent.
Tests
(tasks 1-5 for those who have the last even number in the grade book).
(tasks 5-10 for those who have the last odd number in their grade book).
Task No. 1
94,000 tons arrive at the station and 127,000 tons of packaged unit cargo depart during the year. Determine the number of loaders for processing a given volume: k under = k down = 4; t under = t down = 20 min.; P = 32 t/h.
Task No. 3
On average, the station processes per day: packaged cargo - N day = 25 cargo, N day = 21 cargo; containers - N p days = 49 wag., N o day = 57 wag.; heavy cargo - N day = 32 wag., N o day = 8 wag.
Draw up a balance table, determine k adv, indicate under what conditions k adv can be equal to 2.
Task No. 4
The station loads 185,000 tons of printing paper in rolls
wagon shipments. The following are provided for transportation: 30% covered 4-axle wagons with a body volume of 90 m 3 (P t = 42 t); 25% - with a volume of 106 m 3 (P t = 42 t); 45% - with a volume of 120 m 3 (P t = 45 t). Determine the total number of cars needed to load paper.
Problem No. 5
Determine the number of daily and calendar routes with butane potassium, if Q about year = 1,100,000 tons, and the weight norm of the sending route
Q = 3200 t. Draw up a calendar plan of shipping routes.
Problem No. 6
On average, the following arrives at the station per day: 18 wagons with packaged cargo; 25 wagons with containers; 32 wagons with bulk cargo; 9 wagons with heavy cargo and 11 empty wagons. Determine the number of transfer trains if the number of cars in the transfer train is 27 and fulfill the conditions for decomposition of the transfer train composition.
Problem No. 7
Cargo in containers arrives at the station - Q av day = 400 t, Q max day = 500 t. Determine the coefficient of unevenness of container arrival: k n = ?
Problem No. 8
Determine the duration of the cargo operation with the supply of wagons with containers (3 and 5 tons), which is performed by two gantry cranes KDK - 10, if n = 8 wagons, P = 38.1 cont/h.
Problem No. 9
Determine the minimum and maximum number of wagons supplied to the freight front, if N day = 20 wagons, L fr = 120 m, the time limit of the shunting locomotive for servicing the freight front is 3 hours, t under = 20 min.
Problem No. 10
Determine the costs associated with the downtime of cars waiting for the start of cargo operations, and shunting movements, if N day = 17 wag., e wag-h = 1.5 rub., e lok-h = 65.2 rub., t under = t kill = 20 min., n =3.
Tests (written during a practical lesson).
Test No. 1
(consists of 2 blocks).
Block 1.
Expand the questions
· Document flow in the company's logistics system.
· Efficiency of document management and its adequacy.
· Principles and technology of constructing document flow diagrams.
· Primary accounting documents.
· Mandatory details in primary documents.
· Types of errors and ways to correct them when accounting for inventory items.
· Unified forms of primary accounting documentation for materials accounting.
· Power of attorney (forms No. M-2 and No. M-2a).
· Journal “Accounting for issued powers of attorney”.
· Receipt order (form No. M-4).
· Certificate of acceptance of materials (form No. M-7).
· Limit-fence card (form No. M-8). Requirement - invoice (form No. M-11).
· Invoice for the release of materials to the third party (form No. M-15).
· Materials accounting card (form No. M-17).
· Act on the recording of material assets received during the dismantling and dismantling of buildings and structures (form No. M-35)
· Organization of accounting when receiving goods and materials from individuals, legal entities and legal entities
Block 2.
- (Sea transportation of goods).
2. The concept of "real" communication and the practice of "convenience" flags.
3. International Maritime Organization (IMO).
4. Maritime shipping in conditions of pluralism of legal regimes.
5. Port State Jurisdiction
6. Freedom of navigation on the high seas.
7. International Maritime Satellite Communications Organization (INMARSAT).
8. INCOTERMS rules.
2. (air transportation).
1. International legal regulation of air services.
2. Regulation of commercial activities of air transport enterprises in modern air law.
3. Mandatory insurance during cargo transportation.
4. Improving joint agreements as a form of commercial cooperation between airlines.
5. Liability for damage caused by the aircraft to third parties on the surface.
3. (rail transportation).
1. State regulatory bodies in the field of railway transport: powers, organization of activities.
2. Legal regulation of freight forwarding services for freight transport by rail.
3. Preparation of goods for transportation. Requirements for containers and packaging of goods. Transport marking of goods.
4. Types of departure routes and their organization.
5. Contract for the carriage of goods by rail.
6. Transportation of goods in containers.
7. Types of failure. Actual matter.
4. (road transport).
1. Basic regulations governing the activities of road transport.
2. Motor transport control system.
3. Organization of cargo transportation by road transport.
4. Responsibility of shippers and passengers in road transport.
5. Acts, claims and lawsuits in motor transport.
6. State regulatory bodies in the field of inland road transport: powers, organization of activities.
Control No. 2.
Task 1.
A perishable cargo – strawberries – arrived at the Tyumen-Roshchino airport. Due to meteorological conditions, it was delivered with a delay of more than two days. As a result, the berries completely rotted, and the consignee, JSC Plus Two, refused to receive it. At the same time, the consignee demanded that the airport draw up a commercial act, but he, citing the absence of his guilt, insisted on accepting the cargo from Plus Two JSC.
Give a legal assessment of the current situation.
Task 2.
In accordance with Article 17 of the TUZD of the Russian Federation, OJSC Magnitogorsk Metallurgical Plant entered into a long-term agreement with the Sverdlovsk Railway on the organization of transportation. According to the terms of this agreement, from January 1 to January 10, 2012, the supply of 400 cars, 40 each day, was provided.
The static load for ferrous metals established by the plant is 60 tons per four-axle car. In fact, the station supplied four-axle cars with a carrying capacity of 65 tons for loading on the following days: from January 3 to 7, 40 cars daily; January 2, 8, 9 to 20, since on January 2 the sender had no cargo, on January 8 the loading front was busy, on January 9 there was no empty cargo; On January 1 and 10, no cars were supplied, since on December 28 the sender notified the station of the refusal of cars allocated on January 1, and on January 10 there were snow drifts.
Due to the lack of cargo, the sender loaded only 20 wagons on January 3, on January 6 and 8, due to an emergency stop in production, only 5 wagons each, on the remaining days - all loaded wagons. The plant shipped 65 tons of cargo in each car.
Draw up an account card and calculate the fine for failure to comply with the terms of the contract.
Task 3.
CJSC Lesprom shipped timber in a wagon to OJSC Ufa Plywood Mill. The cargo had a T-shaped marking on it. Upon admission October 10, 1999 wagon onto the recipient's access road, it was established that the height of the timber stack is 2.1 m on one side and 2.4 m on the other. According to the railway bill of lading, the height of the stack was 2.5 m. On this basis, the recipient demanded the participation of the railway in checking the quantity of cargo. However, the destination station refused to check the cargo, citing the safety of the markings.
Is the railway obliged to release the cargo with inspection and in what order are its results documented? What should the recipient do in this case?
Task 4.
Cement was shipped to Murmansk reinforced concrete products via direct mixed rail and water transport. However, the cargo was not delivered to the recipient, and therefore the consignee filed a claim, and then a lawsuit against the shipping company to recover the cost of the lost cargo. The shipping company rejected the claim citing failure to submit a commercial act, and did not recognize the claims due to the plaintiff’s failure to comply with the claim procedure for resolving the dispute.
Give an opinion on the present case.
Task 5.
X5 Retail Group entered into an agreement with the railway for the transportation of tomatoes and apricots from Krasnodar to Moscow. The railroad delivered the wagons for loading his cargo four days late. By this time the fruit began to spoil. As a result, X5 Retail Group suffered significant losses when selling fruit and filed a lawsuit against the railway demanding compensation for losses caused by the delay in the delivery of cars. The railway refused to pay, citing the fact that the delay in the delivery of wagons was caused by the erosion of the railway track due to prolonged heavy rains 100 km from the cargo loading station.
Questions for the problem:
What decision should the court make? (justify your answer with an article in the legal act).
Will the court's decision change if the delay in delivery of wagons occurred due to a delay in unloading them by the previous client?
Routing involves two major components: determining optimal routing paths and transporting groups of information (usually called packets) across an internetwork. In this paper, the latter of these two components is called switching. Switching is relatively simple. On the other hand, route determination can be very complex process
Route determination can be based on various indicators (values resulting from algorithmic calculations on a single variable - for example, route length) or combinations of indicators. Software implementations of routing algorithms calculate route metrics to determine optimal routes to a destination.
To facilitate the route determination process, routing algorithms initialize and maintain routing tables that contain routing information. Routing information changes depending on the routing algorithm used.
Routing algorithms fill routing tables with a certain amount of information. Destination/Next Hop associations tell the router that a certain destination can be optimally reached by sending a packet to a certain router representing the "next hop" on the way to the final destination. When a router receives an incoming packet, it checks the destination address and tries to associate that address with the next forwarding.
Routing tables may also contain other information. "Indicators" provide information about the desirability of a particular channel or path. Routers compare metrics to determine optimal routes. The indicators differ from each other depending on the routing algorithm used. A number of common indicators will be presented and described later in this chapter.
Routers communicate with each other (and maintain their routing tables) by passing various messages. One type of such message is a "routing update" message. Routing updates typically include all or part of the routing table. By analyzing routing update information from all routers, any one of them can build a detailed picture of the network topology. Another example of messages exchanged between routers is a “link-state announcement.” A link-state announcement informs other routers about the status of the sender's links. Link information can also be used to build a complete picture of the network topology. Once the network topology is understood, routers can determine optimal routes to destinations.