Notas estudo JNCIS-ENT parte 6

Nota: Este Post faz parte do guide de Switching.

Graceful Routing Engine Switchover Operations
1. Após o RE serem sincronizados, estes trocam keepalives
2. Se o backup não receber o keepalive do master (em 2 segundos), faz a transição (mastership)
3. O PFE liga-se ao novo master RE
4. o novo master RE e o PFE sincronizam, e o novo master RE enviam os updates necess√°rio para o PFE

Efectuar um switchover do RE:

{master:0}
[email protected]> request chassis routing-engine master switch
Toggle mastership between routing engines ? [yes,no] (no)  yes
{master:0}
[email protected]>
Switch-1 (ttyu0)
login: lab
Logging to master
Password:
— JUNOS 12.2R1.8 built 2012-08-25 01:27:13 UTC
{master:1}
[email protected]>

Outra opcoes:

{master:0}
[email protected]>¬† request chassis routing-engine master ?
Possible completions:
acquire              Attempt to become master Routing Engine
release              Request that other Routing Engine become master
switch               Toggle mastership between Routing Engines

Configuring Graceful Routing Engine Switchover

set chassis redundancy graceful-switchover

! Só é possível executar este comando no backup RE
show system switchover

O master RE replica o state do RE e PFE:

configuration database Рa configuration database é replicada através do comando commit synchronize
chassisd – replica o state do PFE
ksyncd – replica o state do kernel

Nonstop Active Routing

Usa o GRES
Preserva o routing information e as sess√Ķes dos protocolos

Caso o NSR n√£o suporte o protocolo de routing, este opera normalmente

Configuring NSR

set chassis redundancy graceful-switchover
set routing-options nonstop-routing
set system commit synchronize

Monitoring NSR

[email protected]# run show task replication
Stateful Replication: Enabled
RE mode: Master
Protocol        Synchronization Status
OSPF            Complete

Nonstop Bridging

Usa o GRES
Preserva a Layer 2 information e as sess√Ķes dos protocolos

Configuring NSB

set chassis redundancy graceful-switchover
set ethernet-switching-options nonstop-bridging
set system commit synchronize

Output do backup RE com NSB:
{backup:1}
[email protected]> show spanning-tree bridge
STP bridge parameters
Snipped…
If NSB is not enabled the Ethernet subsystem will not be running as illustrated in the following output:
{backup:1}
[email protected]> show spanning-tree bridge
error: the ethernet-switching subsystem is not running

Ethernet Ring Protection Switching (ERPS)

Definido no ITU-T G.8032
Converge em 50 ms, loop-free
A topologia deve ser em ring, e deve conter no mínimo 3 switches
Devido ao fast failover o ERPS pode substituir o STP
Por quest√Ķes de performance n√£o e recomendado ter + de 16 nodos na topologia

Ring Protection Link

Apenas um link age como RPL no ring
O nodo RPL-owner controla o RPL
Em condi√ß√Ķes normais o RPL-owner coloca o RPL em blocked prevenindo loops
Quando um link falha o RPL passa a forwarding, quando o antigo link volta novamente a ficar operacional a RPL passa a blocked

Usando VLANs STP deve ser desativado, pelo que interfere com a comunicação do RPL port

RPL-Owner Node

√önico nodo que envia Ring Automatic Protection Switching (R-APS) messages a notificar os restantes nodos do state do RPL

APS Protocol

Requer um canal dedicado (uma VLAN) para enviar as R-APS entre nodos, de qualquer forma todas as vlans no trunk s√£o afectadas pelo algoritmo APS

Idle State

Quando n√£o existe falhas, todos os nodos estao em idle state.
RPL envia R-APS messages a cada 5 segundos

Signal Failure
Ocorre quando e detectada uma falha num link unblocked do ring

sw1–sw4
|  **  |
sw2–sw3

Entre SW2 e SW3:
Espera pelo expirar do hold interval (default 0), o JunOS n√£o suporta hold time
Muda estado idle para protection
Block as portas falhadas e flush da MAC table
Envia 3 R-APS messages nos primeiros 10 ms seguindo de 1 a cada 5 segundos, ate a condição de signal failed desaparecer

Todos os switchs excepto o SW2 e SW3:
Mudam de estado idle para protection
Flush da MAC table e param de enviar R-APS messages

RPL Owner (SW1):
Desbloqueia RPL
Listen por R-APS messages do SW2 e SW3
Para de enviar R-APS messages

Restoration of a Failed Link

SW2 e SW3:
bloqueiam novamente o link que falhou n√£o enviam R-APS requests
Começam a enviar novos R-APS e com o link bloqueado até receber uma R-APS do SW1, não existindo Flush da MAC table

SW1:(Após não receber request R-APS messages)
Espera pelo expire do restore time (default 5 minutos)
Bloqueia o RPL e transmite R-APS message
Os outros switches unblock das portas e Flush MAC table
Todos os switches mudam do estado protection para idle

ERPS Configuration

Os timers podem ser configurados globalmente ou por ring:
guard-interval (disabled by default) – Previne o o nodo de receber outdated R-APS messages restore-interval – tempo de espera do nodo para processar ERP PDUs

sw1-(east)——–sw4
(west)  ******** |
|
(east)  ******** |
sw2-(west)—–sw3

[email protected]#
!West
set interfaces ge-0/0/4 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/4 unit 0 family ethernet-switching vlan members all
!East
set interfaces ge-0/0/12 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/12 unit 0 family ethernet-switching vlan members all

set vlans control vlan-id 100
set vlans data vlan-id 101

set protocols protection-group ethernet-ring my-erps ring-protection-link-owner east-interface control-channel ge-0/0/12.0

!Definir RPL Interface
set protocols protection-group ethernet-ring my-erps ring-protection-link-owner east-interface ring-protection-link-end

set protocols protection-group ethernet-ring my-erps ring-protection-link-owner west-interface control-channel ge-0/0/4.0

set protocols protection-group ethernet-ring my-erps control-vlan control data-channel vlan data

[email protected]#
!East
set interfaces ge-0/0/4 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/4 unit 0 family ethernet-switching vlan members all
!West
set interfaces ge-0/0/12 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/12 unit 0 family ethernet-switching vlan members all

set vlans control vlan-id 100
set vlans data vlan-id 101

set protocols protection-group ethernet-ring my-erps west-interface control-channel ge-0/0/12.0

set protocols protection-group ethernet-ring my-erps east-interface control-channel ge-0/0/4.0

set protocols protection-group ethernet-ring my-erps control-vlan control data-channel vlan data

show protection-group ethernet-ring aps detail
show protection-group ethernet-ring interface detail
show protection-group ethernet-ring node-state detail

Multiple Spanning Tree Protocol (MSTP)  

Poss√≠vel ter ate 64 inst√Ęncias (MSTIs)
CST permite interligar m√ļltiplas MSTs regions

MSTP Configuration

set protocols mstp configuration-name <configuration-name>
set protocols mstp revision-level <revision-level>
set protocols mstp bridge-priority <priority>
set protocols mstp msti <msti-id> bridge-priority <bridge-priority> vlan (vlan-id | vlan-name)

By default revision-level 0

show spanning-tree mstp configuration
show spanning-tree interface
show spanning-tree bridge

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

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