Allied Telesis AT-WA1104G-10 - Manual (Page 84)

Features in 291-04 84
Version 291-10
C613-10488-00 REV G
CR00014241 BGP
IP Gateway
- This enhancement enables you to force BGP to select the best route on the basis
of network prefix alone, instead of on the basis of preference, then metric, then
network prefix.
To do this:
1. Give the desired dynamic routing protocol a preference of 0, which is the
preference of interface routes, by using the command:
SET IP ROUte PREFerence=0 PROTocol={BGP-ext|BGP-int|OSPF-EXT1|
OSPF-EXT2|OSPF-INTEr|OSPF-INTRa|OSPF-Other|RIP|ALL}
2. Create a route map to give matching routes the same metric as your interface
routes. To change the metric, use the command:
ADD IP ROUTEMap=routemap ENTry=1..4294967295 SET METric=1
3. Add the route map as a filter to the BGP peers by using the command:
ADD BGP PEer=ipadd REMoteas=1..65534 INRoutemap=routemap [other
optional parameters]
The above process gives matching routes the same preference and metric as
interface routes. This forces IP routing to compare the network prefixes of the
interface route and the other routes. IP routing then chooses the most specific
route as the best route for that destination, instead of automatically choosing the
interface route as the best route without considering any other routes which may
have more specific network prefixes.
Y Y Y Y Y – – Y Y Y
CR Module Level Description AR4
00
AR7
x5
AR7
x0S
Rap
ier i
AT
-8800
A
T-8
600
A
T-8
700
XL
x900
-48
A
T-
99
00
A
T-9
800