Mailing List Archive

FWIW, we use "lcp renegotiation always" in the vpdn-group and have
had no issues. Our SP uses J* E series.


interface Virtual-Template1
mtu 1492
ip unnumbered Loopback0
no logging event link-status
load-interval 30
peer default ip address pool dynamic1
ppp authentication pap ppp_local
ppp authorization ppp_local
ppp ipcp dns X.X.X.X X.X.X.X


We do not use ip tcp adjust-mss or ppp mtu adaptive.

At 12:29 PM 07/05/2014, Matthew Melbourne wrote:
>Content-Type: multipart/alternative;
> boundary="----=_NextPart_000_0099_01CF6A19.E3FEB180"
>Content-Language: en-gb
>
>Hi,
>
>Is there a recommended template for vpdn-group and virtual-template
>configuration which provides the best interoperability with
>different Service Providers' LACs? What are users' experiences of
>"lcp renegotiation on-mismatch" and MTU tuning under the
>virtual-template (e.g. ip tcp adjust-mss X and "ppp mtu adaptive", etc)?
>
>Cheers,
>Matt
>
>--
>Matthew Melbourne
>
>_______________________________________________
>cisco-bba mailing list
>cisco-bba@puck.nether.net
>https://puck.nether.net/mailman/listinfo/cisco-bba

---

Clayton Zekelman
Managed Network Systems Inc. (MNSi)
3363 Tecumseh Rd. E
Windsor, Ontario
N8W 1H4

tel. 519-985-8410
fax. 519-985-8409

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cisco-bba mailing list
cisco-bba@puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-bba

Our MTU settings are this:

ip mtu 1492

ip tcp adjust-mss 1452



Frank



From: cisco-bba [mailto:cisco-bba-bounces@puck.nether.net] On Behalf Of
Matthew Melbourne
Sent: Wednesday, May 07, 2014 11:29 AM
To: cisco-bba@puck.nether.net
Subject: [cisco-bba] LCP/MTU tuning template for LNS



Hi,



Is there a recommended template for vpdn-group and virtual-template
configuration which provides the best interoperability with different
Service Providers' LACs? What are users' experiences of "lcp renegotiation
on-mismatch" and MTU tuning under the virtual-template (e.g. ip tcp
adjust-mss X and "ppp mtu adaptive", etc)?



Cheers,

Matt



--

Matthew Melbourne

On 7 May 2014 23:16, Frank Bulk <frnkblk@iname.com> wrote:

> Our MTU settings are this:
>
> ip mtu 1492
>
> ip tcp adjust-mss 1452
>

Has anyone measured the relative performance impact of enabling adjust-mss
on an LNS? Just wondering if it's a massive penalty or a relatively small
one.

Steve

Hi Matt,

All these commands have diffrent aproaches for diffrent problems you
like to solve. While "lcp renegotiation on-mismatch” helps for interopt
issue with diffrent LAC vendors or diffrent endusertechnologies (ISDN,
AoATM, VoETH) on l2tp level, the "ppp mtu adaptive is only usefull if
your transfer links for l2tp and PPPoE supports a bigger MTU than 1500.
This is needed if you want to support MTU 1500 end to end for the
customer. This is mostly not supportet by wholesale partners for
diffrent reasons (political, operations and technical).

The command "tcp adjust-mss 1452" is a workaround for brocken clients if
you have to use a smaller mtu than 1500 which is mostly the case. There
was the early days of xDSL which we also had to clear the df-bit on
packets bigger than 1492 cause FW admins blocked all kind of icmp
packets including type 4 and 12. This is not longer needed in my opinion.

The performance question depends on your router model (72xx vs ASR) and
software version if you can build virtual subinterfaces or not.

Regards
Erich


Am 07.05.14 18:29, schrieb Matthew Melbourne:
> Service Providers’ LACs? What are users’ experiences of “lcp
> renegotiation on-mismatch” and MTU tuning under the virtual-template
> (e.g. ip tcp adjust-mss X and “ppp mtu adaptive”, etc)?
>
_______________________________________________
cisco-bba mailing list
cisco-bba@puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-bba

When I turned it on I did not perceive any performance impact.



Frank



From: cisco-bba [mailto:cisco-bba-bounces@puck.nether.net] On Behalf Of Steve Glendinning
Sent: Thursday, May 08, 2014 7:34 AM
To: cisco-bba@puck.nether.net
Subject: Re: [cisco-bba] LCP/MTU tuning template for LNS





On 7 May 2014 23:16, Frank Bulk <frnkblk@iname.com <mailto:frnkblk@iname.com> > wrote:

Our MTU settings are this:

ip mtu 1492

ip tcp adjust-mss 1452



Has anyone measured the relative performance impact of enabling adjust-mss on an LNS? Just wondering if it's a massive penalty or a relatively small one.



Steve