From: Connary, Julie Ann (jconnary@xxxxxxxxx)
Date: Wed Dec 06 2000 - 23:04:49 GMT-3
Hi All,
I have noticed in the tech tips when redistributing between classfull and
classless protocols
it uses static routes to null 0 to overcome different subnet mask lengths.
http://www.cisco.com/warp/public/105/52.html
Changing the subnet mask of the OSPF domain is difficult, so instead add a
static route in Router GW-2 that points to the OSPF domain with a mask of
255.255.255.0,
but with a next hop of null0. Then, redistribute static routes into RIP.
Here's how to do it:
ip route 128.103.35.0 255.255.255.0 null0
router rip
redistribute static
default metric 1
This allows 128.103.35.0 to be advertised through RIP out the E2/0
interface of Router GW-2. However, Router GW-2 still has more specific
routes learned from OSPF
in its routing table, so the best routing decisions will be made.
My question is, if the OSPF routes are more specific like in the first
example shown above (i.e. longer subnet masks) than say the
RIP routes is it valid to use a summary-address in the OSPF ASBR vs. a
static route to null 0?
The config for the example might be:
router ospf 1
network 128.103.35.0 0.0.0.255 area 0
summary-address 128.103.35.0 255.255.255.0
router rip
network 128.103.0.0
redistribute ospf metric 1
Julie Ann
------------------------------------------------------------------------
Julie Ann Connary
| | Network Consulting Engineer
||| ||| Federal Support Program
.|||||. .|||||. 13635 Dulles Technology Drive,
Herndon VA 20171
.:|||||||||:.:|||||||||:. Pager: 1-888-642-0551
c i s c o S y s t e m s Email: jconnary@cisco.com
------------------------------------------------------------------------
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:25:59 GMT-3