Juniper : VPLS Multi-homing

Juniper

Le multi-homing permet de connecter un customer edge (CE) à plusieurs PE pour assurer ça redondance en évitant les boucles.

Schéma physique

Schéma logique

Pour chacun des PE multi-homé à un même CE, il est nécessaire de configurer le même site ID
Les PE vont ensuite établir un pseudowire vers un seul des routeurs PE multi-homé, le routeur PE à l’origine de l’annonce gagnante.
Cela empêche la création de boucle de niveau 2 avec le CE.
Plus la site préférence est haute plus il y aura de chance que le site soit actif, cela influence la localpref des routes

ex : PE-001 sera actif car il a une préférence supérieure au site de PE-002

PE-001 # set routing-instances VPLS-001-FAB protocols vpls site MULTI-HOMING-FAB-A-SITE-A site-preference primary
ou
PE-001 # set routing-instances VPLS-001-FAB protocols vpls site MULTI-HOMING-FAB-A-SITE-A site-preference 200

PE-002 # set routing-instances VPLS-001-FAB protocols vpls site MULTI-HOMING-FAB-A-SITE-A site-preference backup
ou
PE-002 # set routing-instances VPLS-001-FAB protocols vpls site MULTI-HOMING-FAB-A-SITE-A site-preference 100

Sur chaque PE, le meilleur chemin pour joindre le CE est déterminé en procédant de la manière suivante :

  1. If the advertisement has the down bit set to 0, the advertisement is discarded.
  2. Select the path with a higher preference. The preference attribute is obtained from the site-preference configured using the site-preference statement at the [edit routing-instances routing-instance-name protocols vpls site site-name] hierarchy level. When the site is down, the preference attribute is obtained from the local preference.
  3. If the preference values are the same, select the path with the lower router ID.
  4. If the router IDs are the same, the routes are from the same PE router and the advertisement is considered to be an update. The router ID corresponds to the value of the originator ID for the BGP attribute (if present). Otherwise, the IP address for the remote BGP peer is used.
  5. If the block offset values are the same, the advertisement is considered to be an update.
https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/topics/concept/vpn-vpls-path-selection.html

Once the VPLS path selection process has been completed and the designated VE device has been selected, a pseudowire is signaled between the remote PE router and the local PE router.

Multi-homing avec deux PE

Configuration PE-001

set routing-instances VPLS_MULTI-HOMING instance-type vpls
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 site-identifier 100
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 multi-homing
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 site-preference primary
set routing-instances VPLS_MULTI-HOMING protocols vpls no-tunnel-services
set routing-instances VPLS_MULTI-HOMING interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING route-distinguisher 1.1.1.1:2020
set routing-instances VPLS_MULTI-HOMING vrf-target target:64512:2020

set interfaces ge-0/0/6 description CE-001
set interfaces ge-0/0/6 flexible-vlan-tagging
set interfaces ge-0/0/6 encapsulation flexible-ethernet-services
set interfaces ge-0/0/6 unit 2020 encapsulation vlan-vpls
set interfaces ge-0/0/6 unit 2020 vlan-id 120

Configuration de PE-002

set routing-instances VPLS_MULTI-HOMING instance-type vpls
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 site-identifier 100
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 multi-homing
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-001 site-preference primary
set routing-instances VPLS_MULTI-HOMING protocols vpls no-tunnel-services
set routing-instances VPLS_MULTI-HOMING interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING route-distinguisher 2.2.2.2:2020
set routing-instances VPLS_MULTI-HOMING vrf-target target:64512:2020

set interfaces ge-0/0/6 description CE-001
set interfaces ge-0/0/6 flexible-vlan-tagging
set interfaces ge-0/0/6 encapsulation flexible-ethernet-services
set interfaces ge-0/0/6 unit 2020 encapsulation vlan-vpls
set interfaces ge-0/0/6 unit 2020 vlan-id 120

Configuration de PE-003

set routing-instances VPLS_MULTI-HOMING instance-type vpls
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 interface ge-0/0/7.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 site-identifier 200
set routing-instances VPLS_MULTI-HOMING protocols vpls no-tunnel-services
set routing-instances VPLS_MULTI-HOMING interface ge-0/0/7.2020
set routing-instances VPLS_MULTI-HOMING route-distinguisher 3.3.3.3:2020
set routing-instances VPLS_MULTI-HOMING vrf-target target:64512:2020

set interfaces ge-0/0/7 description CE-001
set interfaces ge-0/0/7 flexible-vlan-tagging
set interfaces ge-0/0/7 encapsulation flexible-ethernet-services
set interfaces ge-0/0/7 unit 2020 encapsulation vlan-vpls
set interfaces ge-0/0/7 unit 2020 vlan-id 120

En fonctionnement nominal l’ensemble du trafic entre le CE et le backbone va transiter par le pe-001

Topologie multi-homing vers deux pe avant bascule

En cas de rupture du lien entre le CE-001 et le PE-001, le trafic va transiter par le lien de backup

Topologie multi-homing vers deux pe après bascule sur le lien de backup

Multi-homing avec un PE

Multi-homing vers un PE

Configuration PE-003

set routing-instances VPLS_MULTI-HOMING instance-type vpls
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 interface ge-0/0/7.2020
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 site-identifier 200
set routing-instances VPLS_MULTI-HOMING protocols vpls no-tunnel-services
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 multi-homing
set routing-instances VPLS_MULTI-HOMING protocols vpls site CE-002 active-interface primary ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING interface ge-0/0/7.2020
set routing-instances VPLS_MULTI-HOMING interface ge-0/0/6.2020
set routing-instances VPLS_MULTI-HOMING route-distinguisher 3.3.3.3:2020
set routing-instances VPLS_MULTI-HOMING vrf-target target:64512:2020

set interfaces ge-0/0/6 description CE-001
set interfaces ge-0/0/6 flexible-vlan-tagging
set interfaces ge-0/0/6 encapsulation flexible-ethernet-services
set interfaces ge-0/0/6 unit 2020 encapsulation vlan-vpls
set interfaces ge-0/0/6 unit 2020 vlan-id 120

set interfaces ge-0/0/7 description CE-001
set interfaces ge-0/0/7 flexible-vlan-tagging
set interfaces ge-0/0/7 encapsulation flexible-ethernet-services
set interfaces ge-0/0/7 unit 2020 encapsulation vlan-vpls
set interfaces ge-0/0/7 unit 2020 vlan-id 120

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