Resumo de Protocolos de Roteamento – EIGRP + OSPF + ISIS + BGPSummary of Routing Protocols – EIGRP + OSPF + ISIS + BGP

Olá Pessoal,

Como estou estudando para BSCI fiz um grande resumão de cada um dos protocolos de roteamento para IPv4.

Um detalhe que deve-se observar é que este resumão foi feito em inglês (:S). Acreditem pessoal, eu consigo pensar melhor em inglês atualmente, especialmente para o estudo. Como o resumo é apresentado em tópicos é interessante para todos.

Para os que estão estudando para a CCNA é interessante dar uma breve olhada para ver o que tem por aí e aproveitar alguns tópicos que são escopo da certificação.

Um abração,

Maurício.

Segue abaixo:

Big Resume

EIGRP:
– Cisco proprietary and distance vector protocol (hybrid).
– Incremental updates.
– Uses Dual and crazy metric with K-values (1,3, Bw e DLY default)
– Establishes neighbors and mainting 3 tables (neighbor, topology, routing table).
– Neighbors must match: authentication, subnet, k-values, hello and dead timers.
– Only protocol that supports unequal cost load-balancing and backup routes (Feasible sucessor).
– If FS > AD the router can be a Feasible Sucessor.
– If there isn’t a feasible sucessor the router sends queryes for its neighbors asking for the route.
– Stuck-in-Active (SIA) is when a network is so big that it searches through it. To solve, router stub or summarization.
– Support ip summary address eigrp in the interface for summarizing the networks.
– Support keychain MD5 and plaintext authentication per interface.
– Support percentage of bandwidth usage, very used in PVC links.
– If you redistribute into EIGRP and don’t set a default-metric the route don’t to go to the routing table, because metric = infinite.Hello Guys,

As I am studying for BSCI great summary of each routing protocols for IPv4.

One detail that should be noted that this was done in English resumão (: S). Believe staff, I can think better in English now, especially for the study. As the summary is presented in topics is interesting for all.

For those who are studying for the CCNA is interesting to give a brief look to see what is out there and enjoy some topics that are scope of certification.

A Abrasive,

Maurício.

Below:

Big Resume

EIGRP:
– Cisco proprietary and distance vector protocol (hybrid).
– Incremental updates.
– Uses Dual and crazy metric with K-values (1,3, Bw e DLY default)
– Establishes neighbors and mainting 3 tables (neighbor, topology, routing table).
– Neighbors must match: authentication, subnet, k-values, hello and dead timers.
– Only protocol that supports unequal cost load-balancing and backup routes (Feasible sucessor).
– If FS > AD the router can be a Feasible Sucessor.
– If there isn’t a feasible sucessor the router sends queryes for its neighbors asking for the route.
– Stuck-in-Active (SIA) is when a network is so big that it searches through it. To solve, router stub or summarization.
– Support ip summary address eigrp in the interface for summarizing the networks.
– Support keychain MD5 and plaintext authentication per interface.
– Support percentage of bandwidth usage, very used in PVC links.
– If you redistribute into EIGRP and don’t set a default-metric the route don’t to go to the routing table, because metric = infinite.

OSPF:
– Open standard protocol, uses the SPF algoritym by Djiskra.
– Link-state protocol. All the neighbors within an area have the same topology (database) table.
– Uses the cost of the links as the metric: 100/BW in MBps, or configured: ip ospf cost.
– Parameters for the neighborship are: area, area type, subnet, network type, timers, authentication
– Neighborship goes as: Down -> init -> 2way (parameters OK) -> Exstart (DR/BDR) -> Exchange (DBD) -> Loading (route exchange) -> Full
– Uses Areas and all of them must have a connection to the Backbone Area, area 0.
– ABR is the border between areas. ASBR is the border between an area and an external routing domain (Autonomous System Boundary Router).
– LSAs can be: 1,2 intra-area    3,4 between areas    5 external    7 nssa (only inside the NSSA area then turns into type 5).
– Areas can be Stub, totally-stub (cisco) and NSSA (not-so-stubby area).
— Stub: LSAs type 5 area substituted by a default route when injected within an area.
— Totally-stub: LSAs 3,4,5 … Set in the ABR, all the others can be stub.
— NSSA: When the ASBR is not in the backbone area this area generates type 7 LSAs. When they get to area 0 they transform into LSA type 5.

– Network types can be: Non-broadcast(NBMA),Point-to-multipoint (open); broadcast, point-to-point, point-to-multipoint nonbroadcast (CISCO).
— Non-broadcast (multiaccess): DR election, neighbor statically set, same subnet
— Point-to-multipoint: NO DR, neighbor auto, same subnet
— Broadcast: LAN (full mesh), DR, same subnet. CISCO MODE
— Point-to-multipoint nonbroadcast: Same as point-to-multipoint, but since it doesn’t support multicast neighbors STATICALLY configured. CISCO MODE
— Point-to-point: PPP, Subif, different subnets, neighbors auto. CISCO MODE

– Has Virtual-links that connects an Area through another to the Backbone area. area [transitarea] virtual-link [router-id].
– Has external metric-types. Type 2 maintain the same value. Type 1 is increased with the cost to each link as it passes by.
– Support summary address for ASBR. Area range for ABR. Both for summarizing the ip infrastructure.
– Support MD5 and plaintext authentication per interface.
– Default redistribution cost 20 (E2), BGP has 1(E2).

ISIS:
– ISO Routing protocol. Uses SPF algoritym.
– Uses NSAP addresses such as [49.0001].[0000.0000.0000].[00] AREA(49 is private) SYSTEMID NSEL(upper layer protocols). NET addr has NSEL 00.
– Routers are only in one area and communicate with a backbone router in another area. There area 2 level os routers and they keep different DBs:
— Level 1: Intra area routing. Keeps records inside an area so the routers must be inside the same area to become neighbors.
— Level 2: Inter area routing. Routers must be in different areas.
— Level 1-2: Is both! Keeps 1 database per Level. This is the router is the border of an area and communicates the intra routers with the inter.

– Is the only one that operates at layer 2.
– Uses TLV (Type, Length, Value) to carry information. This is a modular field, can have IP, routes, IPv6 and so on.
– Uses Metric, default for all links = 10.
– Routing decision goes as: Update, Decision, Forwarding, Receiving.
– Uses CSNP (complete SNP) for getting all the routes and PSNP to acknowledge. PSNP are for one or some routes.
– Has 3 tables: topology, neighbor, routing.
– Neighbors must match: Level, area (= for L1, != for L2), Unique System ID, timers, Authentication.
– On frame-relay must map the clns address.
– Uses links instead of networks. To activate the routing on an interface you must type ip router isis in the interface. isis circuit-type level-1, eg.
– Very bad in NBMA style networks, good to be fully meshed.
– Default for redistribution metric 0.

BGP:
– The only EGP that is a Path-vector routing protocol. If not otimized acts like RIP.
– Huge metric, treated as attributes. The order: Weight; Local_Pref; network or aggregate; AS_Path; i>E>?; MED; eBGP > iBGP… Lowest Router ID;
– Uses 3 tables: neighbor, topology, routing.
– Use autonomous systems. Hops are counted as ASs (AS_Path).
– Neighbors are discovered statically through neighbor 1.1.1.1 remote-as 11.
– iBGP runs within an AS whereas eBGP runs on different AS.
– Communicates through TCP 179.
– Next-hop addresses are always changed in eBGP peers, in iBGP peers the address is not changed. To change: neighbor 1.1.1.1 next-hop-self
– Peer groups are used to group configuration. Very used to configured iBGP peers (very like configs).
– Summarization is managed throuhg aggregate-address, and summary-only can be advertised.
– Very common to use route-maps to modify parameters or to filter routing updates in and outbound.
– If you have a multihoming connection (2 connections to the same provider) you peer to a loopback address. So, you must set the source as the
loopback. neighbor 1.1.1.1 update-source lo 0. BGP packets have a TTL of 1. You must increase this. neighbor 1.1.1.1 ebgp-multihop 2.
– Can have only one AS running in a router.
– Default for redistribution MED is given the IGP value.

OSPF:
– Open standard protocol, uses the SPF algoritym by Djiskra.
– Link-state protocol. All the neighbors within an area have the same topology (database) table.
– Uses the cost of the links as the metric: 100/BW in MBps, or configured: ip ospf cost.
– Parameters for the neighborship are: area, area type, subnet, network type, timers, authentication
– Neighborship goes as: Down -> init -> 2way (parameters OK) -> Exstart (DR/BDR) -> Exchange (DBD) -> Loading (route exchange) -> Full
– Uses Areas and all of them must have a connection to the Backbone Area, area 0.
– ABR is the border between areas. ASBR is the border between an area and an external routing domain (Autonomous System Boundary Router).
– LSAs can be: 1,2 intra-area    3,4 between areas    5 external    7 nssa (only inside the NSSA area then turns into type 5).
– Areas can be Stub, totally-stub (cisco) and NSSA (not-so-stubby area).
— Stub: LSAs type 5 area substituted by a default route when injected within an area.
— Totally-stub: LSAs 3,4,5 … Set in the ABR, all the others can be stub.
— NSSA: When the ASBR is not in the backbone area this area generates type 7 LSAs. When they get to area 0 they transform into LSA type 5.

– Network types can be: Non-broadcast(NBMA),Point-to-multipoint (open); broadcast, point-to-point, point-to-multipoint nonbroadcast (CISCO).
— Non-broadcast (multiaccess): DR election, neighbor statically set, same subnet
— Point-to-multipoint: NO DR, neighbor auto, same subnet
— Broadcast: LAN (full mesh), DR, same subnet. CISCO MODE
— Point-to-multipoint nonbroadcast: Same as point-to-multipoint, but since it doesn’t support multicast neighbors STATICALLY configured. CISCO MODE
— Point-to-point: PPP, Subif, different subnets, neighbors auto. CISCO MODE

– Has Virtual-links that connects an Area through another to the Backbone area. area [transitarea] virtual-link [router-id].
– Has external metric-types. Type 2 maintain the same value. Type 1 is increased with the cost to each link as it passes by.
– Support summary address for ASBR. Area range for ABR. Both for summarizing the ip infrastructure.
– Support MD5 and plaintext authentication per interface.
– Default redistribution cost 20 (E2), BGP has 1(E2).

ISIS:
– ISO Routing protocol. Uses SPF algoritym.
– Uses NSAP addresses such as [49.0001].[0000.0000.0000].[00] AREA(49 is private) SYSTEMID NSEL(upper layer protocols). NET addr has NSEL 00.
– Routers are only in one area and communicate with a backbone router in another area. There area 2 level os routers and they keep different DBs:
— Level 1: Intra area routing. Keeps records inside an area so the routers must be inside the same area to become neighbors.
— Level 2: Inter area routing. Routers must be in different areas.
— Level 1-2: Is both! Keeps 1 database per Level. This is the router is the border of an area and communicates the intra routers with the inter.

– Is the only one that operates at layer 2.
– Uses TLV (Type, Length, Value) to carry information. This is a modular field, can have IP, routes, IPv6 and so on.
– Uses Metric, default for all links = 10.
– Routing decision goes as: Update, Decision, Forwarding, Receiving.
– Uses CSNP (complete SNP) for getting all the routes and PSNP to acknowledge. PSNP are for one or some routes.
– Has 3 tables: topology, neighbor, routing.
– Neighbors must match: Level, area (= for L1, != for L2), Unique System ID, timers, Authentication.
– On frame-relay must map the clns address.
– Uses links instead of networks. To activate the routing on an interface you must type ip router isis in the interface. isis circuit-type level-1, eg.
– Very bad in NBMA style networks, good to be fully meshed.
– Default for redistribution metric 0.

BGP:
– The only EGP that is a Path-vector routing protocol. If not otimized acts like RIP.
– Huge metric, treated as attributes. The order: Weight; Local_Pref; network or aggregate; AS_Path; i>E>?; MED; eBGP > iBGP… Lowest Router ID;
– Uses 3 tables: neighbor, topology, routing.
– Use autonomous systems. Hops are counted as ASs (AS_Path).
– Neighbors are discovered statically through neighbor 1.1.1.1 remote-as 11.
– iBGP runs within an AS whereas eBGP runs on different AS.
– Communicates through TCP 179.
– Next-hop addresses are always changed in eBGP peers, in iBGP peers the address is not changed. To change: neighbor 1.1.1.1 next-hop-self
– Peer groups are used to group configuration. Very used to configured iBGP peers (very like configs).
– Summarization is managed throuhg aggregate-address, and summary-only can be advertised.
– Very common to use route-maps to modify parameters or to filter routing updates in and outbound.
– If you have a multihoming connection (2 connections to the same provider) you peer to a loopback address. So, you must set the source as the
loopback. neighbor 1.1.1.1 update-source lo 0. BGP packets have a TTL of 1. You must increase this. neighbor 1.1.1.1 ebgp-multihop 2.
– Can have only one AS running in a router.
– Default for redistribution MED is given the IGP value.

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Autor: Maurício Bento Ghem

Administrador do blog de estudos www.bentow.com.br Para maiores informações, www.bentow.com.br/sobre

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