Notas estudo JNCIS-ENT parte 10

Nota: Este Post faz parte do guide de Routing.

OSPF Routers

Area border router (ABR) Рconectado a 2 areas, em que uma delas é a area 0
Autonomous system boundary router (ASBR)
Backbone router – contido apenas na area 0
Internal router – contido apenas numa area

OSPF Area Types

Intra-Area routes
External routes
Inter-Area routes

A config de Stub Area injecta uma default route, e remove as external routes.
A Totally Stubby Area recebem apenas a default route. O ABR n√£o envia LSA type 3/4/5
Apenas o Not-so-stubby-area (NNSA) permite injectar rotas externas dentro de uma area, de qualquer forma external routes n√£o s√£o enviados para a area NSSA (ABR n√£o envia LSA type 4/5)

LSA Types

Type 1 – Router
Type 2 – Network
Type 3 – Summary
Type 4 – ASBR Summary
Type 5 – External
Type 7 – NSSA External
Type 6 – Multicast OSPF LSA
Type 8 – External attributes LSA
Type 9 – Opaque LSA (link scope)
Type 10 – Opaque LSA (area scope‚ÄĒused for traffic engineering)
Type 11 – Opaque LSA (AS scope)
Para restringir os LSA type 3 no NSSA usar o comando no-summaries

junOS OS OSPF Support

Suporta:
OSPVv2/v3
Autenticacao (MD5) e IPsec
Summarization
External prefix limits – Limitar o numero de prefixos external usando prefix-export-limit.By default sem limite
Graceful restart (GR) РBy default disabled. O router informa os neighbors antes de reiniciar. Os neighbors continuam a enviar tráfego para o router pensando que este continua na topologia.E definido um período em que os neighbors consideram o router parte de topologia.
Bidirectional Forwarding Detection (BFD) РOs timers sao adaptive. Por exemplo, o timer pode adaptar-se a um valor + alto se a adjacência falhar, ou um neighbor negociar um valor + alto que o configurado

Basic Configuration

!IPv4
set protocols ospf area interface

!IPv6
set protocols ospf3 area interface

Determining the Router ID

!Config explicitamente o RID
set routing-options router-id 192.168.100.1

O junOS define o router-id através de um loopback com mask diferente de 127/8 em primeiro lugar, senão existitir nenhum loopback
O junOS usa o próximo IP disponível, tipicamente a dedicated management interface.

Configuring OSPF

!Manipular custo do OSPF na interface
set protocols ospf area 0.0.0.1 interface ge-1/0/0.0 metric 100
set protocols ospf area 0.0.0.1 interface lo0.0

O custo de uma interface no OSPF e definido pela formula:
cost = reference-bandwidth / bandwidth

!By default reference bandwidth e de 100mbps
[email protected]# set protocols ospf reference-bandwidth ?
Possible completions:
Bandwidth for calculating metric defaults

Defining and Applying the Redistribution Policy

set policy-options policy-statement 2ospf term match-direct-route from protocol direct
set policy-options policy-statement 2ospf term match-direct-route from route-filter 172.18.1.0/24 exact
set policy-options policy-statement 2ospf term match-direct-route then accept

set protocols ospf export 2ospf

[email protected]> show ospf neighbor extensive
Address          Interface              State     ID               Pri  Dead
172.26.1.1       ge-0/0/3.0             Full      192.168.1.1      128    33
Area 0.0.0.1, opt 0x42, DR 172.26.1.2, BDR 172.26.1.1
Up 22:01:45, adjacent 22:01:37
Topology default (ID 0) -> Bidirectional
172.26.2.2       ge-0/0/1.0             Full      192.168.1.3      128    32
Area 0.0.0.0, opt 0x42, DR 172.26.2.2, BDR 172.26.2.1
Up 1d 03:41:28, adjacent 1d 03:41:28
Topology default (ID 0) -> Bidirectional
172.26.3.2       ge-0/0/2.0             Full      192.168.1.3      128    34
Area 0.0.0.0, opt 0x42, DR 172.26.3.2, BDR 172.26.3.1
Up 1d 03:43:14, adjacent 1d 03:43:14
Topology default (ID 0) -> Bidirectional

O campos de output s√£o :
‚ÄĘ Address: Displays the address of the neighbor.
‚ÄĘ Intf: Displays the interface through which the neighbor is reachable.
‚ÄĘ State: Displays the state of the neighbor, which can be¬† Attempt,¬† Down,¬† Exchange ,¬† ExStart,¬† Full,¬† Init,
Loading, or  2Way.
‚ÄĘ ID: Displays the RID of the neighbor.
‚ÄĘ Pri : Displays the priority of the neighb or to become the designated router.
‚ÄĘ Dead: Displays the number of seconds until the neighbor becomes unreachable.
‚ÄĘ area (detail and extensive output only): Displays the area in which the neighbor is located.
‚ÄĘ opt¬† (detail and extensive output only): Displays the option bits from the neighbor.
‚ÄĘ DR (detail and extensive output only): Displays the address of the designated router.
‚ÄĘ BDR¬† (detail and extensive output only): Displays the address of the BDR.
‚ÄĘ Up (detail and extensive output only): Displays the length of time since the neighbor came up.
‚ÄĘ adjacent¬† (detail and extensive output only): Displays the le ngth of time since the adjacency with the neighbor was established.

!Remover as adjacências
clear ospf neighbor

Referências:

Notas estudo JNCIS-ENT parte 1

Notas estudo JNCIS-ENT parte 2

Notas estudo JNCIS-ENT parte 3

Notas estudo JNCIS-ENT parte 4

Notas estudo JNCIS-ENT parte 5

Notas estudo JNCIS-ENT parte 6

Notas estudo JNCIS-ENT parte 7

Notas estudo JNCIS-ENT parte 8

Notas estudo JNCIS-ENT parte 9

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