[ Contents] [ Prev] [ Next] [ Index] [ Report an Error]

Configuring BGP Confederations (Optional)

To help solve BGP scaling problems caused by the IBGP full-mesh requirement, you can divide your AS into sub-ASs called confederations. As Figure 81 shows, the connections between the sub-ASs are made through EBGP sessions, and the internal connections are made through standard IBGP sessions.

In the sample network, AS 17 has two separate confederations (sub-AS 64512 and sub-AS 64513), each of which has multiple routers. Within a sub-AS, an IGP (OSPF, for example) is used to establish network connectivity with internal peers. Between sub-ASs, an external BGP peering session is established.

Figure 81: Typical Network Using BGP Confederations

Image g015035.gif

To configure the BGP confederations shown in Figure 81:

  1. Navigate to the top of the configuration hierarchy in either the J-Web or CLI configuration editor.
  2. Perform the configuration tasks described in Table 140.
  3. If you are finished configuring the router, commit the configuration.
  4. To check the configuration, see Verifying a BGP Configuration.

Table 140: Configuring BGP Confederations

Task

J-Web Configuration Editor

CLI Configuration Editor

Navigate to the Routing options level in the configuration hierarchy.
  1. In the J-Web interface, select Configuration>View and Edit>Edit Configuration.
  2. Next to Routing options, click Edit.

From the [edit] hierarchy level, enter

edit routing-options

Set the AS number to the sub-AS number 64512.

The sub-AS number is a unique AS number that is usually taken from the pool of private AS numbers—64512 through 65535.
  1. In the AS Number box, enter the sub-AS number.
  2. Click OK.

Set the sub-AS number:

set autonomous-system 64512

Navigate to the Confederation level in the configuration hierarchy.
  1. On the main Configuration page next to Routing options, click Edit.
  2. Next to Confederation, click Configure.

From the [edit] hierarchy level, enter

edit routing-options confederation

Set the confederation number to the AS number 17.

In the Confederation as box, enter 17.

Set the confederation AS number:

set 17

Add the sub-ASs as members of the confederation. Every sub-AS within the AS must be added as a confederation member.

  1. Next to Members, click Add new entry.
  2. In the Value box, enter the sub-ASs that are members of this confederation. Separate multiple sub-ASs with a space.

Add members to the confederation:

set 17 members 64512 64513

Using EBGP, configure the peering session between the confederations (from Router A to Router B in this example).

When setting the peer AS number for these sessions, use the sub-AS number rather than the AS number.

See Configuring Point-to-Point Peering Sessions (Required).

Using IBGP, configure internal sessions within a sub-AS. You can configure an IBGP full mesh, or you can configure a route reflector.
[ Contents] [ Prev] [ Next] [ Index] [ Report an Error]

[an error occurred while processing this directive]