[j-nsp] OSPF MTU-IGNORE?

[Harry Reynolds]

I think I follow, but besides the option of ignoring an explicit mtu
mismatch, which Juniper does not support, its seems you could also
reconfigure the JNI's MTU so that it matches the cisco/rest of the
subnet?

<<< default settings


[edit interfaces fe-0/3/1]
harry at vpn06# run show interfaces fe-0/3/1 | match mtu 
  Link-level type: Ethernet, MTU: 1514, Speed: 100mbps, Loopback:
Disabled, Source filtering: Disabled,
    Protocol inet, MTU: 1500
    Protocol mpls, MTU: 1488


<< Smaller


[edit interfaces fe-0/3/1]
harry at vpn06# set mtu 1400 

[edit interfaces fe-0/3/1]
harry at vpn06# commit 
commit complete


[edit interfaces fe-0/3/1]
harry at vpn06# run show interfaces fe-0/3/1 | match mtu    
  Link-level type: Ethernet, MTU: 1400, Speed: 100mbps, Loopback:
Disabled, Source filtering: Disabled,
    Protocol inet, MTU: 1386
    Protocol mpls, MTU: 1374

<<< Bigger


[edit interfaces fe-0/3/1]
harry at vpn06# set mtu 1570 

[edit interfaces fe-0/3/1]
harry at vpn06# commit 
commit complete

[edit interfaces fe-0/3/1]
harry at vpn06# run show interfaces fe-0/3/1 | match mtu    
  Link-level type: Ethernet, MTU: 1570, Speed: 100mbps, Loopback:
Disabled, Source filtering: Disabled,
    Protocol inet, MTU: 1556
    Protocol mpls, MTU: 1544





> -----Original Message-----
> From: Hyunseog Ryu [mailto:r.hyunseog at ieee.org] 
> Sent: Wednesday, July 19, 2006 2:04 PM
> To: Harry Reynolds
> Cc: juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] OSPF MTU-IGNORE?
> 
> The Problem is that one of Cisco router doesn't allow user 
> settable MTU from FastEthernet interface.
> 
> router(config-if)# mtu ?
>    <64-42949672295> MTU size in bytes
> 
> router(config-if)# mtu 1520
> % Interface FastEthernet1/1 does not support user settable mtu.
> 
> router(config-if)# ip mtu
>   <68-1000000>  MTU (bytes)
> 
> router(config-if)# ip mtu 1520
> % Invalid IP MTU specified; minimum 68, maximum 1500
> 
> Because of this one Cisco router, I couldn't use MPLS from 
> this whole subnet.
> I would like to replace this router, but I had no choice.
> 
> 
> Another option was using "ip ospf mtu-ignore" from Cisco, but 
> it seems 
> that JUNOS doesn't support it.
> 
> So I think I'm in deadlock situation until I replaced those 
> problematic 
> Cisco router.
> 
> Hyun
> 
> 
> Harry Reynolds wrote:
> > The last I heard the answer was "no", in part because it 
> breaks section
> > 10.6. of the rfc.
> > 
> > Perhaps you can change the mtu on the JNI to match the cisco?
> > 
> > 
> > Regards
> > 
> > 
> >  
> > 
> >> -----Original Message-----
> >> From: juniper-nsp-bounces at puck.nether.net 
> >> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of 
> Hyunseog Ryu
> >> Sent: Wednesday, July 19, 2006 1:41 PM
> >> To: juniper-nsp at puck.nether.net
> >> Subject: [j-nsp] OSPF MTU-IGNORE?
> >>
> >>
> >> Hi Guys,
> >>
> >> Currently I'm running Cisco/Juniper multi-vendor networks.
> >> >From one of ethernet segment, I would like to change MTU for 
> >> MPLS network.
> >> But the problem is that one of cisco router doesn't allow to 
> >> change MTU size for ehternet card.
> >> So I would like to use "ip ospf mtu-ignore" command from Cisco.
> >> I'm wondering whether Juniper has equivalent command or not.
> >> This will disable OSPF MTU mismatch check for OSPF between routers.
> >>
> >> Thanks.
> >>
> >> Hyun
> >>
> >>
> >> _______________________________________________
> >> juniper-nsp mailing list juniper-nsp at puck.nether.net 
> >> https://puck.nether.net/mailman/listinfo/juniper-nsp
> >>
> > 
> > 
> > 
> 
>