RE: ISIS LSP

Splinter,

In your first post, the task requires the least number of lsp packets. Both
CSNP and PSNP are not LSP so the command csnp-interval or psnp-interval is
not necessary.

Rin.

  _____

From: Splinter [mailto:splinter330_at_gmail.com]
Sent: Sunday, July 12, 2009 4:12 PM
To: Vinu
Cc: Rin; Con Spathas; Cisco certification
Subject: Re: ISIS LSP

Sorry guys,

failed to mention that when you enable isis network point-to-point the isis
csnp-interval is added by default.

should those timers also be adjust as 10sec is the default.

Splinter

On Sun, Jul 12, 2009 at 10:56 AM, Splinter <splinter330_at_gmail.com> wrote:

Guys,

thanx for all the inputs, This is where my confusion comes in...

what about csnp-interval or psnp-interval?

* Complete sequence number PDUs (CSNPs)-Contain a complete list of all
LSPs in the IS-IS database. CSNPs are sent periodically on all links, and
the receiving systems use the information in the CSNP to update and
synchronize their LSP databases. The designated router multicasts CSNPs on
broadcast links in place of sending explicit acknowledgments for each LSP.
* Partial sequence number PDUs (PSNPs)-Multicast by a receiver when it
detects that it is missing an LSP; that is, when its LSP database is out of
date. The receiver sends a PSNP to the system that transmitted the CSNP,
effectively requesting that the missing LSP be transmitted. That router, in
turn, forwards the missing LSP to the requesting router.

and isis retransmit-interval?

Usage Guidelines

The setting of the seconds argument should be conservative, or needless
retransmission will result.

This command has no effect on LAN (multipoint) interfaces. On point-to-point
links, the value can be increased to enhance network stability.

Retransmissions occur only when LSPs are dropped. So setting the seconds
argument to a higher value has little effect on reconvergence. The more
neighbors routers have, and the more paths over which LSPs can be flooded,
the higher this value can be made.

The value should be higher for serial lines.

Examples

The following example configures serial interface 0 for retransmission of
IS-IS LSP, every 60 seconds for a large serial line:

interface serial 0
 isis retransmit-interval 60

Regards Splinter

On Sun, Jul 12, 2009 at 8:59 AM, Vinu <vinupeter_at_gmail.com> wrote:

Thanks Rin,

i guess we can live with it if convergence time is not a constraint... and i
guess increasing the lsp MTU also will reduce number of LSP packets. in the
Link... Even though have never worked on real life ISIS network :-(

On Sun, Jul 12, 2009 at 10:32 AM, Rin <rintrum_at_gmail.com> wrote:

Hi Vinu,

The command lsp-gen-interval 120 will increase the latency between
consecutive LSP generations. So if we consider in an fix amount of time, the
LSP exchanged will be less. However, this will reduce the convergence time
of the network. Thus, I'd not use this command for this requirement.

Rin.

  _____

From: Vinu [mailto:vinupeter_at_gmail.com]
Sent: Sunday, July 12, 2009 12:44 PM
To: Con Spathas
Cc: Rin; Splinter; Cisco certification
Subject: Re: ISIS LSP

i guess you'll need to add

# lsp-gen-interval 120 (it's maximum value in seconds)

On Sun, Jul 12, 2009 at 7:00 AM, Con Spathas <ccie19226_at_googlemail.com>
wrote:

I'd concur with that.

I've seen those settings in the IS-IS Network Design Solutions book by
Martey/Sturges as well as some DocCD doco...
For example:
http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/isfscbp_ps63
50_TSD_Products_Configuration_Guide_Chapter.html#wp1055077

On Sun, Jul 12, 2009 at 2:45 AM, Rin<rintrum_at_gmail.com> wrote:
> Hi Splinter,
>
> I would configure as below:
> - specify only L1 or L2 LSP
> - Change LSP Remaining Lifetime to maximum value: max-lsp-lifetime 65535
> - Change LSP Refresh Interval to maximum value: lsp-refresh-interval 65000
>
> Just my thought, any other ideas?
>
> Rin
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Splinter
> Sent: Sunday, July 12, 2009 1:20 AM
> To: Cisco certification
> Subject: ISIS LSP
>
> Hi,
>
> I need to make sure that the least number of lsp packets are sent between
> routers on a point to point ethernet segment.
>
>
> Thank you
>
> Splinter
>
>
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Received on Sun Jul 12 2009 - 22:29:55 ART