HP 6125XLG R2306-HP 6125XLG Blade Switch Layer 3 - IP Routing Configuration Gu - Page 231

Configuring a BGP confederation, Configuring confederation compatibility, Configuring BGP GR

Page 231 highlights

A confederation contains sub-ASs. In each sub-AS, IBGP peers are fully meshed. Sub-ASs establish EBGP connections in between. Configuring a BGP confederation After you split an AS into multiple sub-ASs, configure a router in a sub-AS as follows: 1. Enable BGP and specify the AS number of the router. For more information, see "Enabling BGP." 2. Specify the confederation ID. From an outsider's perspective, the sub-ASs of the confederation is a single AS, which is identified by the confederation ID. 3. If the router needs to establish EBGP connections to other sub-ASs, you must specify the peering sub-ASs in the confederation. A confederation can contain a maximum of 32 sub-ASs. The AS number of a sub-AS is effective only in the confederation. To configure a BGP confederation: Step 1. Enter system view. 2. Enter BGP view. Command system-view bgp as-number 3. Configure a confederation ID. confederation id as-number 4. Specify peering sub-ASs in the confederation peer-as confederation. as-number-list Remarks N/A N/A By default, no confederation ID is configured. By default, no peering sub-AS is specified. Configuring confederation compatibility If any routers in the confederation do not comply with RFC 3065, enable confederation compatibility to allow the router to work with those routers. To configure confederation compatibility: Step 1. Enter system view. 2. Enter BGP view. 3. Enable confederation compatibility. Command system-view bgp as-number confederation nonstandard Remarks N/A N/A By default, confederation compatibility is disabled. Configuring BGP GR GR ensures forwarding continuity when BGP restarts or an active/standby switchover occurs. Two routers are required to complete a GR process. The following are router roles in a GR process. • GR Restarter-Performs GR upon a BGP restart or active/standby switchover. • GR Helper-Helps the GR Restarter to complete the GR process. A device can act as a GR Restarter and GR Helper at the same time. BGP GR works as follows: 220

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220
A confederation contains sub-ASs. In each sub-AS, IBGP peers are fully meshed. Sub-ASs establish EBGP
connections in between.
Configuring a BGP confederation
After you split an AS into multiple sub-ASs, configure a router in a sub-AS as follows:
1.
Enable BGP and specify the AS number of the router. For more information, see "
Enabling BGP
."
2.
Specify the confederation ID. From an outsider's perspective, the sub-ASs of the confederation is
a single AS, which is identified by the confederation ID.
3.
If the router needs to establish EBGP connections to other sub-ASs, you must specify the peering
sub-ASs in the confederation.
A confederation can contain a maximum of 32 sub-ASs. The AS number of a sub-AS is effective only in
the confederation.
To configure a BGP confederation:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Configure a confederation ID.
confederation id
as-number
By default, no confederation ID is
configured.
4.
Specify peering sub-ASs in the
confederation.
confederation peer-as
as-number-list
By default, no peering sub-AS is
specified.
Configuring confederation compatibility
If any routers in the confederation do not comply with RFC 3065, enable confederation compatibility to
allow the router to work with those routers.
To configure confederation compatibility:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Enable confederation
compatibility.
confederation nonstandard
By default, confederation
compatibility is disabled.
Configuring BGP GR
GR ensures forwarding continuity when BGP restarts or an active/standby switchover occurs.
Two routers are required to complete a GR process. The following are router roles in a GR process.
GR Restarter
—Performs GR upon a BGP restart or active/standby switchover.
GR Helper
—Helps the GR Restarter to complete the GR process.
A device can act as a GR Restarter and GR Helper at the same time.
BGP GR works as follows: