Маршрутизация - Revision history

Anko: /* Рутиращи протоколи */

2013-01-07T11:38:46Z

Рутиращи протоколи

Anko: /* Рутиращи протоколи */

2013-01-07T11:38:32Z

Рутиращи протоколи

Show changes

Anko: /* Path vector protocol */

2013-01-07T11:33:20Z

Path vector protocol

Anko: /* IGRP/EIGRP */

2013-01-07T11:21:39Z

IGRP/EIGRP

Anko: /* Distance vector algorithms */

2013-01-07T11:16:31Z

Distance vector algorithms

Anko: /* Алгоритми на рутиращи протоколи */

2013-01-07T10:17:50Z

Алгоритми на рутиращи протоколи

Anko: /* Рутиращи протоколи */

2013-01-07T10:08:32Z

Рутиращи протоколи

Anko: /* Динамично рутиране */

2013-01-07T10:08:01Z

Динамично рутиране

Anko: /* Динамично рутиране */

2013-01-07T10:06:22Z

Динамично рутиране

Anko: /* Статично рутиране */

2013-01-07T09:53:00Z

Статично рутиране

@@ Line 109: / Line 109: @@
 ==Рутиращи протоколи==
 ===RIP ===
 RIP (routing information protocol) e широко използван маршрутизиращ протокол с вектор на разстоянието. Той е подходящ предимно за малки мрежи, в които относително рядко настъпват промени в топологията.

← Older revision		Revision as of 11:33, 7 January 2013
Line 96:		Line 96:

	Path vector routing is used for inter-domain routing. It is similar to distance vector routing. In path vector routing we assume there is one node (there can be many) in each autonomous system which acts on behalf of the entire autonomous system. This node is called the speaker node. The speaker node creates a routing table and advertises it to neighboring speaker nodes in neighboring autonomous systems. The idea is the same as distance vector routing except that only speaker nodes in each autonomous system can communicate with each other. The speaker node advertises the path, not the metric of the nodes, in its autonomous system or other autonomous systems. Path vector routing is discussed in RFC 1322; the path vector routing algorithm is somewhat similar to the distance vector algorithm in the sense that each border router advertises the destinations it can reach to its neighboring router. However, instead of advertising networks in terms of a destination and the distance to that destination, networks are advertised as destination addresses and path descriptions to reach those destinations. A route is defined as a pairing between a destination and the attributes of the path to that destination, thus the name, path vector routing, where the routers receive a vector that contains paths to a set of destinations. The path, expressed in terms of the domains (or confederations) traversed so far, is carried in a special path attribute that records the sequence of routing domains through which the reachability information has passed.		Path vector routing is used for inter-domain routing. It is similar to distance vector routing. In path vector routing we assume there is one node (there can be many) in each autonomous system which acts on behalf of the entire autonomous system. This node is called the speaker node. The speaker node creates a routing table and advertises it to neighboring speaker nodes in neighboring autonomous systems. The idea is the same as distance vector routing except that only speaker nodes in each autonomous system can communicate with each other. The speaker node advertises the path, not the metric of the nodes, in its autonomous system or other autonomous systems. Path vector routing is discussed in RFC 1322; the path vector routing algorithm is somewhat similar to the distance vector algorithm in the sense that each border router advertises the destinations it can reach to its neighboring router. However, instead of advertising networks in terms of a destination and the distance to that destination, networks are advertised as destination addresses and path descriptions to reach those destinations. A route is defined as a pairing between a destination and the attributes of the path to that destination, thus the name, path vector routing, where the routers receive a vector that contains paths to a set of destinations. The path, expressed in terms of the domains (or confederations) traversed so far, is carried in a special path attribute that records the sequence of routing domains through which the reachability information has passed.
		+
		+	Each entry in the routing table contains the destination network, the next router and the path to reach the destination.

	===Сравнение на рутиращи алгоритмни===		===Сравнение на рутиращи алгоритмни===

← Older revision		Revision as of 11:21, 7 January 2013
Line 111:		Line 111:
	===IS-IS===		===IS-IS===
	===IGRP/EIGRP===		===IGRP/EIGRP===
		+	===BGP===

@@ Line 62: / Line 62: @@
 ===Distance vector algorithms===
-Distance vector algorithms use the Bellman-Ford algorithm. This approach assigns a number, the cost, to each of the links between each node in the network. Nodes will send information from point A to point B via the path that results in the lowest total cost (i.e. the sum of the costs of the links between the nodes used).
+На всяка връзка между два нода се дава някаква стойност. Всеки нод ще препаща съобщение от точка А към точка B по пътя, който има най малка сумарна стойност.
-The algorithm operates in a very simple manner. When a node first starts, it only knows of its immediate neighbours, and the direct cost involved in reaching them. (This information, the list of destinations, the total cost to each, and the next hop to send data to get there, makes up the routing table, or distance table.) Each node, on a regular basis, sends to each neighbour its own current idea of the total cost to get to all the destinations it knows of. The neighbouring node(s) examine this information, and compare it to what they already 'know'; anything which represents an improvement on what they already have, they insert in their own routing table(s). Over time, all the nodes in the network will discover the best next hop for all destinations, and the best total cost.
+При първоначалното включване на един нод, той знае единствено за връзките със своите съседи и стойността на тези връзките. Той прави таблица на тези връзки .
-When one of the nodes involved goes down, those nodes which used it as their next hop for certain destinations discard those entries, and create new routing-table information. They then pass this information to all adjacent nodes, which then repeat the process. Eventually all the nodes in the network receive the updated information, and will then discover new paths to all the destinations which they can still "reach". eg RIPV1,RIPV2
+(This information, the list of destinations, the total cost to each, and the next hop to send data to get there, makes up the routing table, or distance table.)
 ===Link-state algorithms===

@@ Line 61: / Line 61: @@
 == Алгоритми на рутиращи протоколи ==
-Distance vector algorithms
+===Distance vector algorithms===
 Distance vector algorithms use the Bellman-Ford algorithm. This approach assigns a number, the cost, to each of the links between each node in the network. Nodes will send information from point A to point B via the path that results in the lowest total cost (i.e. the sum of the costs of the links between the nodes used).
@@ Line 69: / Line 68: @@
 When one of the nodes involved goes down, those nodes which used it as their next hop for certain destinations discard those entries, and create new routing-table information. They then pass this information to all adjacent nodes, which then repeat the process. Eventually all the nodes in the network receive the updated information, and will then discover new paths to all the destinations which they can still "reach". eg RIPV1,RIPV2
-[edit]
-Link-state algorithms
+===Link-state algorithms===
 When applying link-state algorithms, each node uses as its fundamental data a map of the network in the form of a graph. To produce this, each node floods the entire network with information about what other nodes it can connect to, and each node then independently assembles this information into a map. Using this map, each router then independently determines the least-cost path from itself to every other node using a standard shortest paths algorithm such as Dijkstra's algorithm. The result is a tree rooted at the current node such that the path through the tree from the root to any other node is the least-cost path to that node. This tree then serves to construct the routing table, which specifies the best next hop to get from the current node to any other node.
-[edit]
-Optimised Link State Routing algorithm
+===Optimised Link State Routing algorithm ===
 A link-state routing algorithm optimised for mobile ad-hoc networks is the Optimised Link State Routing Protocol (OLSR).[1] OLSR is proactive; it uses Hello and Topology Control (TC) messages to discover and disseminate link state information through the mobile ad-hoc network. Using Hello messages, each node discovers 2-hop neighbor information and elects a set of multipoint relays (MPRs). MPRs distinguish OLSR from other link state routing protocols.
-[edit]
-Path vector protocol
+===Path vector protocol===
 Distance vector and link state routing are both intra-domain routing protocols. They are used inside an autonomous system, but not between autonomous systems. Both of these routing protocols become intractable in large networks and cannot be used in Inter-domain routing. Distance vector routing is subject to instability if there are more than a few hops in the domain. Link state routing needs huge amount of resources to calculate routing tables. It also creates heavy traffic due to flooding.
 Path vector routing is used for inter-domain routing. It is similar to distance vector routing. In path vector routing we assume there is one node (there can be many) in each autonomous system which acts on behalf of the entire autonomous system. This node is called the speaker node. The speaker node creates a routing table and advertises it to neighboring speaker nodes in neighboring autonomous systems. The idea is the same as distance vector routing except that only speaker nodes in each autonomous system can communicate with each other. The speaker node advertises the path, not the metric of the nodes, in its autonomous system or other autonomous systems. Path vector routing is discussed in RFC 1322; the path vector routing algorithm is somewhat similar to the distance vector algorithm in the sense that each border router advertises the destinations it can reach to its neighboring router. However, instead of advertising networks in terms of a destination and the distance to that destination, networks are advertised as destination addresses and path descriptions to reach those destinations. A route is defined as a pairing between a destination and the attributes of the path to that destination, thus the name, path vector routing, where the routers receive a vector that contains paths to a set of destinations. The path, expressed in terms of the domains (or confederations) traversed so far, is carried in a special path attribute that records the sequence of routing domains through which the reachability information has passed.
-[edit]
-Comparison of routing algorithms
+===Сравнение на рутиращи алгоритмни===
 Distance-vector routing protocols are simple and efficient in small networks and require little, if any, management. However, traditional distance-vector algorithms have poor convergence properties due to the count-to-infinity problem.

← Older revision		Revision as of 10:08, 7 January 2013
Line 96:		Line 96:

	==Рутиращи протоколи==		==Рутиращи протоколи==
		+	===RIP===
		+	===OSPF===
		+	===IS-IS===
		+	===IGRP/EIGRP===

← Older revision		Revision as of 10:08, 7 January 2013
Line 48:		Line 48:

	Примери за такива протоколи са RIP - Routing Information Protocol и OSPF (Open-Shortest-Path-First protocol). Дънамичното рутиране пробладава в Интернет, но изисква съответните познания за правилното му конфигуриране.		Примери за такива протоколи са RIP - Routing Information Protocol и OSPF (Open-Shortest-Path-First protocol). Дънамичното рутиране пробладава в Интернет, но изисква съответните познания за правилното му конфигуриране.
		+
		+	Adaptive routing describes the capability of a system, through which routes are characterized by their destination, to alter the path that the route takes through the system in response to a change in conditions.[1] The adaptation is intended to allow as many routes as possible to remain valid (that is, have destinations that can be reached) in response to the change.
		+
		+	People using a transport system can display adaptive routing. For example, if a local railway station is closed, people can alight from a train at a different station and use another method, such as a bus, to reach their destination. Another example of adaptive routing can be seen within financial markets. For example, ASOR or Adaptive Smart Order Router (developed by Quod Financial), takes routing decisions dynamically and based on real-time market events.
		+
		+	The term is commonly used in data networking to describe the capability of a network to 'route around' damage, such as loss of a node or a connection between nodes, so long as other path choices are available. There are several protocols used to achieve this:
		+	RIP
		+	OSPF
		+	IS-IS
		+	IGRP/EIGRP

	== Алгоритми на рутиращи протоколи ==		== Алгоритми на рутиращи протоколи ==

← Older revision		Revision as of 10:06, 7 January 2013
Line 49:		Line 49:
	Примери за такива протоколи са RIP - Routing Information Protocol и OSPF (Open-Shortest-Path-First protocol). Дънамичното рутиране пробладава в Интернет, но изисква съответните познания за правилното му конфигуриране.		Примери за такива протоколи са RIP - Routing Information Protocol и OSPF (Open-Shortest-Path-First protocol). Дънамичното рутиране пробладава в Интернет, но изисква съответните познания за правилното му конфигуриране.

−	== ~~Динамично рутиране~~ ==	+	== Алгоритми на рутиращи протоколи ==
		+
		+	Distance vector algorithms
		+	Main article: Distance-vector routing protocol
		+
		+	Distance vector algorithms use the Bellman-Ford algorithm. This approach assigns a number, the cost, to each of the links between each node in the network. Nodes will send information from point A to point B via the path that results in the lowest total cost (i.e. the sum of the costs of the links between the nodes used).
		+
		+	The algorithm operates in a very simple manner. When a node first starts, it only knows of its immediate neighbours, and the direct cost involved in reaching them. (This information, the list of destinations, the total cost to each, and the next hop to send data to get there, makes up the routing table, or distance table.) Each node, on a regular basis, sends to each neighbour its own current idea of the total cost to get to all the destinations it knows of. The neighbouring node(s) examine this information, and compare it to what they already 'know'; anything which represents an improvement on what they already have, they insert in their own routing table(s). Over time, all the nodes in the network will discover the best next hop for all destinations, and the best total cost.
		+
		+	When one of the nodes involved goes down, those nodes which used it as their next hop for certain destinations discard those entries, and create new routing-table information. They then pass this information to all adjacent nodes, which then repeat the process. Eventually all the nodes in the network receive the updated information, and will then discover new paths to all the destinations which they can still "reach". eg RIPV1,RIPV2
		+	[edit]
		+	Link-state algorithms
		+	Main article: Link-state routing protocol
		+
		+	When applying link-state algorithms, each node uses as its fundamental data a map of the network in the form of a graph. To produce this, each node floods the entire network with information about what other nodes it can connect to, and each node then independently assembles this information into a map. Using this map, each router then independently determines the least-cost path from itself to every other node using a standard shortest paths algorithm such as Dijkstra's algorithm. The result is a tree rooted at the current node such that the path through the tree from the root to any other node is the least-cost path to that node. This tree then serves to construct the routing table, which specifies the best next hop to get from the current node to any other node.
		+	[edit]
		+	Optimised Link State Routing algorithm
		+	Main article: Optimized Link State Routing Protocol
		+
		+	A link-state routing algorithm optimised for mobile ad-hoc networks is the Optimised Link State Routing Protocol (OLSR).[1] OLSR is proactive; it uses Hello and Topology Control (TC) messages to discover and disseminate link state information through the mobile ad-hoc network. Using Hello messages, each node discovers 2-hop neighbor information and elects a set of multipoint relays (MPRs). MPRs distinguish OLSR from other link state routing protocols.
		+	[edit]
		+	Path vector protocol
		+	Main article: Path vector protocol
		+
		+	Distance vector and link state routing are both intra-domain routing protocols. They are used inside an autonomous system, but not between autonomous systems. Both of these routing protocols become intractable in large networks and cannot be used in Inter-domain routing. Distance vector routing is subject to instability if there are more than a few hops in the domain. Link state routing needs huge amount of resources to calculate routing tables. It also creates heavy traffic due to flooding.
		+
		+	Path vector routing is used for inter-domain routing. It is similar to distance vector routing. In path vector routing we assume there is one node (there can be many) in each autonomous system which acts on behalf of the entire autonomous system. This node is called the speaker node. The speaker node creates a routing table and advertises it to neighboring speaker nodes in neighboring autonomous systems. The idea is the same as distance vector routing except that only speaker nodes in each autonomous system can communicate with each other. The speaker node advertises the path, not the metric of the nodes, in its autonomous system or other autonomous systems. Path vector routing is discussed in RFC 1322; the path vector routing algorithm is somewhat similar to the distance vector algorithm in the sense that each border router advertises the destinations it can reach to its neighboring router. However, instead of advertising networks in terms of a destination and the distance to that destination, networks are advertised as destination addresses and path descriptions to reach those destinations. A route is defined as a pairing between a destination and the attributes of the path to that destination, thus the name, path vector routing, where the routers receive a vector that contains paths to a set of destinations. The path, expressed in terms of the domains (or confederations) traversed so far, is carried in a special path attribute that records the sequence of routing domains through which the reachability information has passed.
		+	[edit]
		+	Comparison of routing algorithms
		+
		+	Distance-vector routing protocols are simple and efficient in small networks and require little, if any, management. However, traditional distance-vector algorithms have poor convergence properties due to the count-to-infinity problem.
		+
		+	This has led to the development of more complex but more scalable algorithms for use in large networks. Interior routing mostly uses link-state routing protocols such as OSPF and IS-IS.
		+
		+	A more recent development is that of loop-free distance-vector protocols (e.g., EIGRP). Loop-free distance-vector protocols are as robust and manageable as native distance-vector protocols, but avoid counting to infinity, and have good worst-case convergence times.
		+
		+	==Рутиращи протоколи==

@@ Line 26: / Line 26: @@
 Приципно цялата мрежа може да бъде конфигурирана статично, но по този начин мрежата не е устойчива на повреда в даден нод. Ако има промяна и повреда в мрежата трафика няма да може да се пренасочи. Трябва да бъдат обновени съответните рутиращи таблици или да бъде отсранена повредата, за да може мрежата да функционира нормално.
-n entire network can be configured using static routes, but this type of configuration is not fault tolerant. When there is a change in the network or a failure occurs between two statically defined nodes, traffic will not be rerouted. This means that anything that wishes to take an affected path will either have to wait for the failure to be repaired or the static route to be updated by the administrator before restarting its journey. Most requests will time out (ultimately failing) before these repairs can be made. There are, however, times when static routes can improve the performance of a network. Some of these include stub networks and default routes.
+====Пример ====
-To configure a static route to network 10.10.20.0/24, pointing to a next-hop router with the IP address of 192.168.100.1, type: (Note that this example is written in the Cisco IOS command line syntax and will only work on certain Cisco routers[2])
+To configure a static route to network 10.10.20.0/24, pointing to a next-hop router with the IP address of 192.168.100.1, type:
-ip route 10.10.20.0 255.255.255.0 192.168.100.1Destination network	10.10.20.0
+ Cisco IOS
-subnet	255.255.255.0
+ ip route 10.10.20.0 255.255.255.0 192.168.100.1
-next-hop	192.168.100.1
+ Linux
+ Cisco IOS
-  The other option is to define a static route with reference to the outgoing interface which is connected to the next hop towards the destination network.
+  ip route 10.10.20.0 255.255.255.0 FastEthernet 0/0
+ Linux
-ip route 10.10.20.0 255.255.255.0 Serial 0/0Destination network	10.10.20.0
+ route add -net 10.10.20.0 netmask 255.255.255.0 dev eth0
 ===Динамично рутиране ===