3com S7906E Manuel De Montage

 

1-29 

Follow these steps to enable the comparison of MED of routes from confederation peers: 

Enter system view 

— 

Enter BGP view 

bgp as-number 

— 

Enable the comparison of MED of 
routes from confederation peers 

Optional 

Not enabled by default 

 

The MED attributes of routes from confederation peers are not compared if their AS-path attributes 

contain AS numbers that don’t belong to the confederation. For example, there are three routes: 

AS-path attributes of them are 65006 65009, 65007 65009 and 65008 65009, and MED values of them 

are 2, 3, and 1. Because the third route contains an AS number that does not belong to the 

confederation, the first route becomes the optimal route.  

 

By default, when advertising routes to an iBGP peer/peer group, a BGP router does not set itself as the 

next hop. However, to ensure a BGP peer can find the correct next hop in some cases, you need to 

configure the router as the next hop for routes sent to the peer.  

For example, as shown in the figure below, Router A and Router B establish an eBGP neighbor 

relationship, and Router B and Router C establish an iBGP neighbor relationship. When Router B 

advertises a network learned from Router A to Router C, if Router C has no route to IP address 

1.1.1.1/24, you need to configure Router B to set itself as the next hop (3.1.1.1/24) for the route to be 

sent to Router C. 

Figure 1-17 Next hop attribute configuration 

 

 

If a BGP router has two peers on a common broadcast network, it does not set itself as the next hop for 

routes sent to an eBGP peer by default. As shown below, Router A and Router B establish an eBGP 

neighbor relationship, and Router B and Router C establish an iBGP neighbor relationship. They are on 

the same broadcast network 1.1.1.0/24. When Router B sends eBGP routes to Router A, it does not set 

itself as the next hop by default. However, you can configure Router B to set it as the nexthop 

(1.1.1.2/24) for routes sent to Router A by using the peer next-hop-local command as needed.