Riverbed SteelHead 3070-SD, User Manual

Page: 52 / 124

52 | Configuring BGP, OSPF, Static Routing, and Route Retraction on SteelHead SD
Configuring BGP on SteelHead SD
2. Select the BGP tab.
Figure 7-5. Configuring MED settings
3. Under Multi exit discriminator, enable one of these MED settings:
– Deterministic MED - Click On to ensure the comparison of the MED variable when choosing
routes advertised by different peers in the same AS. The default value is Off .
– Always_compare MED - Click On to ensure the comparison of the MED for paths from
neighbors in different autonomous systems. This setting useful when multiple service providers
or enterprises agree on a uniform policy for setting MED. The default value is
Off .
4. Click Submit .
Configuring BGP route summarization
With route summarization, a new network prefix with a shorter prefix length is advertised into BGP.
Summarizing prefixes conserves router resources and accelerates best path calculation by reducing the
size of the BGP table. Summarization also provides increased stability by reducing routing loops.
You can configure BGP route summarization using one of these modes:
• Manual - Creates a static route and advertises the network via a network statement. The summary
route will always be advertised even if the networks are not available.
• Automatic - Creates a network range. When viable routes that match the network range enter the
BGP table, an aggregate route is created. On the originating router, the aggregated prefix sets the
next hop to Null 0. The route to Null 0 is automatically created by BGP to prevent routing loops.