- A virtual community of network engineers
 Home  BookStore  StudyNotes  Links  Archives  StudyRooms  HelpWanted  Discounts  Login
RE: Multiple Default Routes [7:70914] posted 06/20/2003
[Chronological Index] [Thread Index] [Top] [Date Prev][Date Next] [Thread Prev][Thread Next]

This may be different in some IOS version, but in every version I have used
static routes pointing to an interface maintain the static route
administrative distance of one.  (IP addresses removed to protect the
innocent ;)

Via interface:

ip route x.x.x.x Serial3/0/0/7:0

ar01-nyc2.ny#sh ip route x.x.x.x
Routing entry for x.x.x.x/28
  Known via "static", distance 1, metric 0 (connected)
  Routing Descriptor Blocks:
  * directly connected, via Serial3/0/0/7:0
      Route metric is 0, traffic share count is 1

Via IP:

ip route x.x.x.x x.x.x.x x.x.x.x

ar01-nyc2.ny#sh ip route x.x.x.x
Routing entry for x.x.x.x/27
  Known via "static", distance 1, metric 0
  Routing Descriptor Blocks:
  * x.x.x.x
      Route metric is 0, traffic share count is 1

-----Original Message-----
From: Troy Leliard [mailto:troy.leliard@xxxxxxxxxxxx] 
Sent: Friday, June 20, 2003 11:24 AM
To: cisco@xxxxxxxxxxxxxx
Subject: Re: Multiple Default Routes [7:70914]

Using a next hop of an interface or IP address does have slightly 
different behaviour.  Using an interface as the next hop actually giev 
the route an AD of 0 (ie a directly connected route), while that 
pointing to an IP has an AD of 1.  Small, but significant differences, 
especially when redistributing static / connected into routing 
protocols/  (eg redisitribute a connected interface, ie a route that 
points to an interface, and it will show up as an internally learnt 
EIGRP route, while the route pointing to an IP address will show up as 
nan externally learnt route (ad=170), and thus differnt behaviour.)

There are slight performance gains to be made by referencing an outbound 
interface as the next hop too, as the router doesn't have to do a lookup 
to "resolve" which interface the next hop IP address is on.

Poulin, Darnell wrote:
> Here are the entries we have...
> ip route
> ip route 10
> ip route 200 
> It's pretty straight-forward, so I'm not sure what the problem can be. We
> are using ver 12 of the IOS.
> -----Original Message-----
> From: Zsombor Papp [mailto:zpapp@xxxxxxxxx]
> Sent: Thursday, June 19, 2003 10:42 AM
> To: cisco@xxxxxxxxxxxxxx
> Subject: RE: Multiple Default Routes [7:70914]
> At 10:27 AM 6/19/2003 +0000, Chirag Arora wrote:
>>How are the default routes defined: using the next hop or using local
>>interface?? In case of local interface they will not flush out even if the
>>interface is down. In case of next hop it should.
> IMHO the route should be removed even if it's pointing to the local 
> interface. With what version of IOS have you seen the behavior you
> Nevertheless, the best thing is to reference both a next hop and a local 
> interface in the static route, as explained on the web page Srivathsan
> Thanks,
> Zsombor
>>Chirag Arora
>>-----Original Message-----
>>From: Poulin, Darnell [mailto:darnell.poulin@xxxxxx]
>>Sent: Thursday, June 19, 2003 1:48 PM
>>To: cisco@xxxxxxxxxxxxxx
>>Subject: Multiple Default Routes [7:70914]
>>Does anyone know of any problems using multiple static default routes on a
>>router using different metrics? We seem to be having a problem getting the
>>second or third default route to kick in once the primary one fails. On
>>secondary default route we are using a metric of 10, and on the third
>>default route we are using a metric of 200.
>>Information contained and transmitted by this E-MAIL is proprietary to
>>Wipro Limited and is intended for use only by the individual or entity
>>to which it is addressed, and may contain information that is privileged,
>>confidential or exempt from disclosure under applicable law. If this is
>>a forwarded message, the content of this E-MAIL may not have been sent
>>with the authority of the Company. If you are not the intended recipient,
>>an agent of the intended recipient or a  person responsible for delivering
>>the information to the named recipient,  you are notified that any use,
>>distribution, transmission, printing, copying or dissemination of this
>>information in any way or in any manner is strictly prohibited. If you
>>received this communication in error, please delete this mail & notify us
>>immediately at mailadmin@xxxxxxxxxxx

Message Posted at:
FAQ, list archives, and subscription info:
Report misconduct and Nondisclosure violations to abuse@xxxxxxxxxxxxxx