[j-nsp] IS-IS bug in 7.3?

[Harry Reynolds]

Sound like you are the DID. As I recall, the configurable timers are for
non-dis. Once elected DIS they are cut by 1/3 to promote rapid recovery
from DID failure. This has been the case for several version, since 4.x
at least. Any chance you can confirm by setting a low priority, say a
value of 1? This should force another router with default pri of 64 to
supersede DIS functions. I suspect that you have a priority tie and MAC
address is coming into play making it seem like a version thing.

HTHs


>From docs:

Modifying the Hello Interval
Routers send hello packets at a fixed interval on all interfaces to
establish and
maintain neighbor relationships. This interval is advertised in the
hello interval field
in the hello packet. By default, a designated intersystem (DIS) router
sends hello
packets every 3 seconds, and a non-DIS router sends hello packets every
9 seconds.

 

> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net 
> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Gordon Smith
> Sent: Wednesday, September 21, 2005 5:37 PM
> To: juniper-nsp at puck.nether.net
> Subject: [j-nsp] IS-IS bug in 7.3?
> 
> Hi all,
> 
> Just came across something interesting while testing IGP 
> convergence and configuration.
> 
> I have a backbone network segment that has both Juniper and 
> Cisco devices on it.
> The routers exchange loopback address routes via IS-IS, then 
> stand up BGP adjacencies to the loopbacks of neighbouring 
> routers. This works as intended.
> 
> The problem I've come across is in JUNOS 7.3 code, and 
> concerns IS-IS hold timers.
> 
> The default should be 27 sec hold-time with a 9 sec hello-interval.
> JUNOS 7.2R1.7 and Cisco IOS honor this.
> In JUNOS 7.3R1.6 however, the hold-time is drastically 
> reduced and will not accept a change via config.
> 
> This is what I should see:
> 
> fe-0/0/0.0
>   Index: 66, State: 0x806, Circuit id: 0x2, Circuit type: 2
>   LSP interval: 100 ms, CSNP interval: 10 s
>   Level Adjacencies Priority Metric Hello (s) Hold (s) 
> Designated Router
>     2             7       64     10     9.000       27 jcore2.02 (not
> us)
> 
> But on the mis-behaving box I get:
> 
> IS-IS interface database:
> fe-0/0/0.0
>   Index: 75, State: 0x806, Circuit id: 0x2, Circuit type: 2
>   LSP interval: 100 ms, CSNP interval: 10 s
>   Level Adjacencies Priority Metric Hello (s) Hold (s) 
> Designated Router
>     2             7       64     10     3.000        9 jcore2.02 (us)
> 
> Doing this:
> 
> interface fe-0/0/0.0 {
>     checksum;
>     level 2 {
>         hello-interval 9;
>         hold-time 27;
>     }
> }
> 
> Results in no change whatsoever...
> 
> Bug in the code? Anyone else seen this? Even restarted rpd, 
> but to no avail...
> 
> An old piece of documentation on Juniper's site (for 4.4) 
> states that 9 sec hold-time is the default, but that's not 
> what I'm seeing here.
> 
> Cheers,
> Gordon
> 
> 
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