Understanding
Routing Protocol, Atonomous System, Distance Vector Routing, Routing
Loops and Multiple Methods Minimizing Routing Loops
In a local network or LAN, it is generally all devices connected to one or more switches using the LAN cable. As with the wireless network, wireless devices connected to the adapter using radio frequency.
As for the connection between the LAN through WAN network, each of them connected through a router and routing protocol. Cisco Router you, she can send and passes the packet only if he has programmed in its routing table. In order for a router could route / missed packet, a router must know at least:
Address (IP) Receiver
Router neighbor, with which he can study a wider network
Route / track passable
Best route to each network
Routing information
Understanding routing
Routing is the process of data transfer through internetwork from one network LAN to another LAN network. While a Bridge connecting segment-2 network and share traffic as needed according to the hardware address. A router receives and forwards traffic along the appropriate / correct according to address software. Konsequensinya, Bridges operate at the data link layer (Layer 2) of the OSI model, so called Bridge Layer 2 devices. While the Router works on the network layer / Layer 3 and commonly referred to as Layer 3 devices.
In the IP network, routing is done according to the IP routing table. All IP hosts use a routing table to skip / forward traffic received from other routers or hosts.Understanding Routing - Communication Internetwork
Understanding Routing - Communication Internetwork
IP routing protocol
IP routing protocol provides communication between the router. IP routing protocol has one main purpose - to fill the routing table with a path (route) and the latest best he could get. Although it may sound simple, but the process is very complicated and it's options. Some terminology should also be understood in relation to these routing protocols.
Routing protocol routing table filled with routing information, such as RIP or IGRP
Routed protocol is a protocol with karakteristic layer 3 network layer defines logical addressing and routing, such as IP and IPX. Packet-2 is defined by a portion of the network layer-2 protocol can be routed / missed.
Routing refers to the routing protocol type such as link-state or distance-vector.
IP routing table to fill the routing table with a valid path and loop-free, in addition to the routing protocol also keep the looping. Route / track was added to the routing tebel containing
Subnet number, eg 172.200.100.0
interface out - where the packet is forwarded and sent to the subnet, eg s0, s1, or eo
IP address of the next or the next hop router that should receive packets destined for that subnet
In general, routing protocols have several goals as summarized below:
Dynamically learn and fill the routing table with a path for all subnets on the network
If there is more than one path to a subnet, the routing protocol puts the best path into the routing table.
Tells if the track in the routing table is no longer valid, and remove the track from rauting table
If a path in the routing table in clear and learned another track from the surrounding routers available, it will be added to the routing table.
To add a new track, or replace it with a new track as soon as possible. The time between the loss of route / track and attempt to get a new track called convergence time replacement.
The latter is to prevent the occurrence of routing loops.
It is necessary to understand the concepts and methods involved routing that will help us in the administration of the router.
Autonomous Systems and Routing Protocols
As we know, a router connects two network / network. A network / network is a segment with a unique network address. But with IP, the term network can define two different meanings:
A segment with a unique IP address (usually refers to a subnet)
A network IP address given to an organization (the organization can download the subnet network address into multiple addresses)
Each organization is assigned a network address from the ISP is considered as an "autonomous system (AS)". After that the organization could have been free to form a large network, or divide its network into subnets-2.Understanding routing - Autonomous System
Understanding routing - Autonomous System
In the diagram above is an Autonomous System or AS. From the outside (ISP) Autonomous System as a whole is identified as a network address class B. In the Autonomous System, a router is used to divide the network into subnets-2. Routers that are in the Autonomous System only know the route / path that exists in the Autonomous System itself, but not memantain information about the route outside the Autonomous System. Router on the border / border referred to as AS Autonomous System border router. This router maintains route information route both inside and outside the U.S. border router.
Each Autonomous System AS is identified by a number. AS numbers can be local in administration, or in the register to the Internet if it is tangent to the public network / Internet.
Router-2 within an Autonomous System is used to download the segment (subnet) of a network. and also, the router-2 can be used to connect the U.S. together. Routers use routing protocols to dynamically locate path / route, build routing tables, and making decisions about how to send packets through the internetwork.
Routing protocols can be classified based on whether they are inside or pass traffic between Autonomous Systems.
Interior Gateway Protocol (IGP) - the protocol traffic passing within the Autonomous System
Exterior Gateway Protocol (EGP) - the protocol traffic passing out or inter-Autonomous System
Border Gateway Protocol (BGP) - is a development version of EGP were passing traffic between Autonomous Systems.
Understanding a routine - IGP and EGP
Understanding a routine - IGP and EGP
In this diagram is an Autonomous System that connects to the Internet through an ISP router. Router-2 that are in the Autonomous System run Interior Gateway Protocol (IGP) to find a route in the Autonomous System. AS border router that connects the ISP Autonomous System and the second run Interior Gateway Protocol (IGP) to communicate with the router-2 in the Autonomous System, and Exterior Gateway Protocol (EGP) to communicate with the router beyond the Autonomous System. The U.S. Border routers collect information outside the Autonomous System routing.
Here is the IP routing protocols supported by Cisco routers.
RIP (Routing Information Protocol)
IGRP (Interior Gateway Routing Protocol)
IS-IS (Intermediate System-to-Intermediate System)
OSPF (Open Shortest Path First OSPF)
Distance Vector Routing
RIP and IGRP both use distance vector routing method, although IGRP offers many development of RIP.Understanding Routing - Hop Count
Understanding Routing - Hop Count
In the following example, we use the hop count as a metric to determine the network cost. Router # 1 only knows-2 network that is connected to the router is just the network A and B. And each has a price-2 network 1 hop count to pass from one network A to B or vice versa. This knowledge is in broadcast to the router-2 neighbors, so the router # 2 who knows only network B and C in the table to add to the knowledge network A hop count is 2.
Router # 2 know the network that is connected to it just the network B and C, and the router broadcasts its knowledge to router # 3 and # 1. Router # 1 to add to the table valuable network C 2 hop count. Router # 3 who only know the network C and D in the table adds a valuable network B 2 hop count. So on router-2 study the routing information from the router next to them so they can be described as follows in the table below is after all the routers reach convergence.Router 1 Router 2 Router 3Network A = 1 A = 2 Network hop hop hop Network A = 3Network B = 1 B = 1 network hop hop hop Network B = 2Network C = 2 C = 1 network hop hop hop Network C = 1Network Network D = 3 D = 2 hop hop hop Network D = 1
Distance Vector routing-2 has the following principles:
Routers send updates only to neighboring routers
Routers send routing table that knows all the neighbors router
Table is shipped with a certain time interval, where each router is configured with one-second update interval
The router modifies the table based on the information received from the router teangganya.
Because the router-2 using the method of distance vector routing to send the whole routing table information with a certain interval of time, they are susceptible to a condition called a routing loop (also referred to as a condition of count-to-infinity). As with bridging loops in STP, routing loop occurs when two routers share different information.
Method-2 the following can be used to minimize the effects of routing loops:
Split horizon, split method allows the router to come perform trackin its information from the router where. Routers do not report routing information to the router on the same track. In other words, the router does not report information back to the router that gives information.
Distance Vector-Split Horizon
Distance Vector-Split Horizon
Split horizon with poison reverse, also called poison reverse method. Router-2 fixed route to send information back to the next-hop router, but to preach the path as unreachable. If the next-hop router was learned that the path / router can still be achieved, then the information is ignored. If the path turns a time-out, the route immediately on the set as unreachable. Convergence occurs faster than the simple method of poison reverse split horizon. However, generating greater traffic for the entire routing table in a broadcast each time an update is sent.
Distance Vector - Split Horizon Poison Reverse dg
Distance Vector - Split Horizon Poison Reverse dg
Triggered updates, router-2 which receives updated information (change) going to broadcast these changes immediately rather than waiting interval. In this way the router is broadcasting its routing table periodically, but if there are changes to the router is broadcasting immediately direct these changes.
Distance Vector - Triggered Method
Distance Vector - Triggered Method
Hold downs, with this method, the router-2 will "hold" (hold) an update that seeks to restore the link expired. The time period generally reflect the time required to reach convergence on the network.
Distance Vector - Hold down
Distance Vector - Hold down
Distance Vector method has the following advantages:
Proved relatively stable, which is the original routing algorithm
Relatively easily maintained and implemented
Bandwidth requirements can be ignored for typical LAN environment.
Disadvantages of Distance vector is as follows:
It took a relatively long time to reach convergence (updates sent by a certain time interval).
The router calculates its routing table before forwarding table changes
Vulnerable occurrence of routing loops
Can be very large bandwidth requirements for WAN or LAN environment is
In a local network or LAN, it is generally all devices connected to one or more switches using the LAN cable. As with the wireless network, wireless devices connected to the adapter using radio frequency.
As for the connection between the LAN through WAN network, each of them connected through a router and routing protocol. Cisco Router you, she can send and passes the packet only if he has programmed in its routing table. In order for a router could route / missed packet, a router must know at least:
Address (IP) Receiver
Router neighbor, with which he can study a wider network
Route / track passable
Best route to each network
Routing information
Understanding routing
Routing is the process of data transfer through internetwork from one network LAN to another LAN network. While a Bridge connecting segment-2 network and share traffic as needed according to the hardware address. A router receives and forwards traffic along the appropriate / correct according to address software. Konsequensinya, Bridges operate at the data link layer (Layer 2) of the OSI model, so called Bridge Layer 2 devices. While the Router works on the network layer / Layer 3 and commonly referred to as Layer 3 devices.
In the IP network, routing is done according to the IP routing table. All IP hosts use a routing table to skip / forward traffic received from other routers or hosts.Understanding Routing - Communication Internetwork
Understanding Routing - Communication Internetwork
IP routing protocol
IP routing protocol provides communication between the router. IP routing protocol has one main purpose - to fill the routing table with a path (route) and the latest best he could get. Although it may sound simple, but the process is very complicated and it's options. Some terminology should also be understood in relation to these routing protocols.
Routing protocol routing table filled with routing information, such as RIP or IGRP
Routed protocol is a protocol with karakteristic layer 3 network layer defines logical addressing and routing, such as IP and IPX. Packet-2 is defined by a portion of the network layer-2 protocol can be routed / missed.
Routing refers to the routing protocol type such as link-state or distance-vector.
IP routing table to fill the routing table with a valid path and loop-free, in addition to the routing protocol also keep the looping. Route / track was added to the routing tebel containing
Subnet number, eg 172.200.100.0
interface out - where the packet is forwarded and sent to the subnet, eg s0, s1, or eo
IP address of the next or the next hop router that should receive packets destined for that subnet
In general, routing protocols have several goals as summarized below:
Dynamically learn and fill the routing table with a path for all subnets on the network
If there is more than one path to a subnet, the routing protocol puts the best path into the routing table.
Tells if the track in the routing table is no longer valid, and remove the track from rauting table
If a path in the routing table in clear and learned another track from the surrounding routers available, it will be added to the routing table.
To add a new track, or replace it with a new track as soon as possible. The time between the loss of route / track and attempt to get a new track called convergence time replacement.
The latter is to prevent the occurrence of routing loops.
It is necessary to understand the concepts and methods involved routing that will help us in the administration of the router.
Autonomous Systems and Routing Protocols
As we know, a router connects two network / network. A network / network is a segment with a unique network address. But with IP, the term network can define two different meanings:
A segment with a unique IP address (usually refers to a subnet)
A network IP address given to an organization (the organization can download the subnet network address into multiple addresses)
Each organization is assigned a network address from the ISP is considered as an "autonomous system (AS)". After that the organization could have been free to form a large network, or divide its network into subnets-2.Understanding routing - Autonomous System
Understanding routing - Autonomous System
In the diagram above is an Autonomous System or AS. From the outside (ISP) Autonomous System as a whole is identified as a network address class B. In the Autonomous System, a router is used to divide the network into subnets-2. Routers that are in the Autonomous System only know the route / path that exists in the Autonomous System itself, but not memantain information about the route outside the Autonomous System. Router on the border / border referred to as AS Autonomous System border router. This router maintains route information route both inside and outside the U.S. border router.
Each Autonomous System AS is identified by a number. AS numbers can be local in administration, or in the register to the Internet if it is tangent to the public network / Internet.
Router-2 within an Autonomous System is used to download the segment (subnet) of a network. and also, the router-2 can be used to connect the U.S. together. Routers use routing protocols to dynamically locate path / route, build routing tables, and making decisions about how to send packets through the internetwork.
Routing protocols can be classified based on whether they are inside or pass traffic between Autonomous Systems.
Interior Gateway Protocol (IGP) - the protocol traffic passing within the Autonomous System
Exterior Gateway Protocol (EGP) - the protocol traffic passing out or inter-Autonomous System
Border Gateway Protocol (BGP) - is a development version of EGP were passing traffic between Autonomous Systems.
Understanding a routine - IGP and EGP
Understanding a routine - IGP and EGP
In this diagram is an Autonomous System that connects to the Internet through an ISP router. Router-2 that are in the Autonomous System run Interior Gateway Protocol (IGP) to find a route in the Autonomous System. AS border router that connects the ISP Autonomous System and the second run Interior Gateway Protocol (IGP) to communicate with the router-2 in the Autonomous System, and Exterior Gateway Protocol (EGP) to communicate with the router beyond the Autonomous System. The U.S. Border routers collect information outside the Autonomous System routing.
Here is the IP routing protocols supported by Cisco routers.
RIP (Routing Information Protocol)
IGRP (Interior Gateway Routing Protocol)
IS-IS (Intermediate System-to-Intermediate System)
OSPF (Open Shortest Path First OSPF)
Distance Vector Routing
RIP and IGRP both use distance vector routing method, although IGRP offers many development of RIP.Understanding Routing - Hop Count
Understanding Routing - Hop Count
In the following example, we use the hop count as a metric to determine the network cost. Router # 1 only knows-2 network that is connected to the router is just the network A and B. And each has a price-2 network 1 hop count to pass from one network A to B or vice versa. This knowledge is in broadcast to the router-2 neighbors, so the router # 2 who knows only network B and C in the table to add to the knowledge network A hop count is 2.
Router # 2 know the network that is connected to it just the network B and C, and the router broadcasts its knowledge to router # 3 and # 1. Router # 1 to add to the table valuable network C 2 hop count. Router # 3 who only know the network C and D in the table adds a valuable network B 2 hop count. So on router-2 study the routing information from the router next to them so they can be described as follows in the table below is after all the routers reach convergence.Router 1 Router 2 Router 3Network A = 1 A = 2 Network hop hop hop Network A = 3Network B = 1 B = 1 network hop hop hop Network B = 2Network C = 2 C = 1 network hop hop hop Network C = 1Network Network D = 3 D = 2 hop hop hop Network D = 1
Distance Vector routing-2 has the following principles:
Routers send updates only to neighboring routers
Routers send routing table that knows all the neighbors router
Table is shipped with a certain time interval, where each router is configured with one-second update interval
The router modifies the table based on the information received from the router teangganya.
Because the router-2 using the method of distance vector routing to send the whole routing table information with a certain interval of time, they are susceptible to a condition called a routing loop (also referred to as a condition of count-to-infinity). As with bridging loops in STP, routing loop occurs when two routers share different information.
Method-2 the following can be used to minimize the effects of routing loops:
Split horizon, split method allows the router to come perform trackin its information from the router where. Routers do not report routing information to the router on the same track. In other words, the router does not report information back to the router that gives information.
Distance Vector-Split Horizon
Distance Vector-Split Horizon
Split horizon with poison reverse, also called poison reverse method. Router-2 fixed route to send information back to the next-hop router, but to preach the path as unreachable. If the next-hop router was learned that the path / router can still be achieved, then the information is ignored. If the path turns a time-out, the route immediately on the set as unreachable. Convergence occurs faster than the simple method of poison reverse split horizon. However, generating greater traffic for the entire routing table in a broadcast each time an update is sent.
Distance Vector - Split Horizon Poison Reverse dg
Distance Vector - Split Horizon Poison Reverse dg
Triggered updates, router-2 which receives updated information (change) going to broadcast these changes immediately rather than waiting interval. In this way the router is broadcasting its routing table periodically, but if there are changes to the router is broadcasting immediately direct these changes.
Distance Vector - Triggered Method
Distance Vector - Triggered Method
Hold downs, with this method, the router-2 will "hold" (hold) an update that seeks to restore the link expired. The time period generally reflect the time required to reach convergence on the network.
Distance Vector - Hold down
Distance Vector - Hold down
Distance Vector method has the following advantages:
Proved relatively stable, which is the original routing algorithm
Relatively easily maintained and implemented
Bandwidth requirements can be ignored for typical LAN environment.
Disadvantages of Distance vector is as follows:
It took a relatively long time to reach convergence (updates sent by a certain time interval).
The router calculates its routing table before forwarding table changes
Vulnerable occurrence of routing loops
Can be very large bandwidth requirements for WAN or LAN environment is
Tidak ada komentar:
Posting Komentar