From: Scott Morris (swm@emanon.com)
Date: Mon Aug 18 2003 - 11:59:45 GMT-3
Now, now, be nice... If he changed his MTU, then absolutely it's an
issue... Default operation though even accepting frame sizes to 1518
(as I noted) does not make the MTU 1518...
So... If you don't mess with the MTU, there is no issue working with a
3550. If you mess with the MTU on ANY device, then there will be an
issue trying to get things to work right!
Out of the box, by default though, the MTU is not 1518. (Caveat (since
I want to avoid correction): On any of the numerous 3550's I've seen)
If you have purchased a used one, perhaps things are different. *shrug*
But judging by reading the original message about "I created vlan 10",
then things should be "normal". And I believe I also note "If you did,
that's what's messed up. If you didn't, look at the bug id referenced
above. Try a different IOS."
:)
Scott
-----Original Message-----
From: John Matijevic [mailto:matijevi@bellsouth.net]
Sent: Monday, August 18, 2003 9:34 AM
To: Seonghui; Scott Morris; 'Mustafa M Bayramov'; ccielab@groupstudy.com
Subject: Re: cat3550 cannot establish ospf nei with router/s
Hello Seong,
I am glad it is working for you now. It looks like it was an mtu issue
all along as I had first mentioned. Scott Morris had mentioned the
following: It's not an MTU issue at all... Check out the IOS release
you have. Bug CSCdv61151 mentions this. I want to correct Scott in that
this was a MTU issue. Even a quadruple CCIE can be wrong sometimes.
:)
Sincerely,
Matijevic
----- Original Message -----
From: "Seonghui" <Seonghui@vads.com>
To: "Scott Morris" <swm@emanon.com>; "'Mustafa M Bayramov'"
<spyroot@azeronline.com>; <ccielab@groupstudy.com>
Sent: Monday, August 18, 2003 5:22 AM
Subject: RE: cat3550 cannot establish ospf nei with router/s
> Yup, I got it working after deleting vlan.dat file and reloaded,
> followed
by
> set system mtu 1500 and another reload for it to take effect. OSPF
> works fine after that.
>
> But does every new switch comes with MTU 1518? I received 2 cat 35500
> at
the
> same time, one by default is 1518 and the other one is 1500. Does it
> mean that we have to check the MTU size on a switch before enabling L3
> routing protocols in the exam?
>
> part of troubleshooting huh :)
>
> Thank you all for your help.
>
> -----Original Message-----
> From: Scott Morris [mailto:swm@emanon.com]
> Sent: Monday, August 18, 2003 5:10 AM
> To: 'Mustafa M Bayramov'; 'seonghui'; ccielab@groupstudy.com
> Subject: RE: cat3550 cannot establish ospf nei with router/s
>
>
> I would agree... Before an RMA, do a 'write erase' and 'del vlan.dat'
> then reload the sucker and see what happens.
>
> Karma? :)
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of Mustafa M Bayramov
> Sent: Sunday, August 17, 2003 1:13 PM
> To: 'seonghui'; 'Scott Morris'; ccielab@groupstudy.com
> Subject: RE: cat3550 cannot establish ospf nei with router/s
>
>
> Make delete vlan.dat and you will see switch will set default MTU 1518
>
> To fix this you can change system MTU ( need restart switch ) Adjust
> MTU per VLAN. Adjust MTU for SWI interface. Set ip ospf mtu-ignore for
> ospf on both routers.
>
> Regards
>
>
> Mustafa M Bayramov
>
> CISSP
> CCNP,CCDP,Cisco Security Specialist
> Network engineer and security analyst
>
> Azercell Telecom J.V.
>
> "I know nothing except the fact of my ignorance." Socrates
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of seonghui
> Sent: Saturday, August 16, 2003 11:20 PM
> To: 'Scott Morris'; ccielab@groupstudy.com
> Subject: RE: cat3550 cannot establish ospf nei with router/s
>
> Hi Scott,
>
> OK, this sounds reasonable. But I have tried the same setting and
> config. on another identical cat3550 switch, running the same IOS code
> (flash:c3550-i5q3l2-mz.121-13.EA1a/c3550-i5q3l2-mz.121-13.EA1a.bin)
> and it works! OSPF nei adj formed almost instantly with the
> router...this puzzles me. can i just send the switch for RMA?
>
> anyway, thanks group for your help. I better leave this problem alone,
> else i'll be wasting too much time and never move on.
>
> regards-SH
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Scott Morris
> Sent: Sunday, August 17, 2003 3:04 AM
> To: 'John Matijevic'; 'MMoniz'; 'seonghui'; ccielab@groupstudy.com
> Subject: RE: cat3550 cannot establish ospf nei with router/s
>
>
> It's not an MTU issue at all... Check out the IOS release you have.
> Bug CSCdv61151 mentions this.
>
> I just set it up on a 3550 and three different routers (2610 and two
> different 3620's) and ospf came up immediately. No MTU playing,
> nothing funky, nothing bizarre, just simple network command and *POOF*
> there were neighbors and routes and reachability!
>
> The switch is wholly aware of different things because it's a switch.
> :) Looking at show interface, the MTU should be 1500 on everything.
> 1518 is allowed, but that's not a L3 MTU, that's the L3 MTU + L2
> header. Even doing show interface on a trunk port, you'll see the same
> MTU even though it now expects 18 additional bytes plus some extra for
> the trunking (depending on your protocol). SO.... There shouldn't be
> a need in this instance to change MTU at all.
>
> If you did, that's what's messed up. If you didn't, look at the bug
> id referenced above. Try a different IOS.
>
> HTH,
>
> Scott
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of John Matijevic
> Sent: Saturday, August 16, 2003 2:25 PM
> To: MMoniz; seonghui; ccielab@groupstudy.com
> Subject: Re: cat3550 cannot establish ospf nei with router/s
>
>
> MMoniz,
> MTU on router int fa0/0 is of course 1500 while MTU on vlan 10 is
> 1518. This looks like a mtu mismatch, I was having him change the mtu
> on vlan 10 to 1500 to match. We are still waiting for the results.
> Sincerely, Matijevic
> ----- Original Message -----
> From: "MMoniz" <ccie2002@tampabay.rr.com>
> To: "seonghui" <seonghui@vads.com>; "'John Matijevic'"
> <matijevi@bellsouth.net>; <ccielab@groupstudy.com>
> Sent: Saturday, August 16, 2003 2:19 PM
> Subject: RE: cat3550 cannot establish ospf nei with router/s
>
>
> > It should be 1500. It looked like an MTU mismatch except the debugs
> > would normally show it.
> >
> >
> > 22:38:05: OSPF: Send DBD to 133.5.5.5 on Serial0 seq 0xF5F opt 0x42
> > flag
> 0x7
> > len 32
> > 22:38:05: OSPF: Retransmitting DBD to 133.5.5.5 on Serial0 [11]
> > 22:38:05: OSPF: Rcv DBD from 133.5.5.5 on Serial0 seq 0x2122 opt
> > 0x42 flag 0x7 len 32 mtu 1500 state EXSTART
> > 22:38:05: OSPF: Nbr 133.5.5.5 has larger interface MTU
> > R3#
> >
> >
> > This is default on my 3550
> >
> > VDL-CAT#sho in vlan 2
> > Vlan2 is up, line protocol is up
> > Hardware is EtherSVI, address is 000b.fdf0.ba00 (bia
000b.fdf0.ba00)
> > Internet address is 133.5.23.8/24
> > MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
> >
> > What code are you running on your Cat?
> >
> >
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf
> > Of
>
> > seonghui
> > Sent: Saturday, August 16, 2003 2:05 PM
> > To: 'John Matijevic'; ccielab@groupstudy.com
> > Subject: RE: cat3550 cannot establish ospf nei with router/s
> >
> >
> > Hi Matijevic,
> >
> > MTU on router int fa0/0 is of course 1500 while MTU on vlan 10 is
> > 1518. I tried changing them but router doesn't allow me to do so.
> >
> > any clue?
> >
> > regards - SH
> >
> > -----Original Message-----
> > From: John Matijevic [mailto:matijevi@bellsouth.net]
> > Sent: Sunday, August 17, 2003 1:55 AM
> > To: seonghui; ccielab@groupstudy.com
> > Subject: Re: cat3550 cannot establish ospf nei with router/s
> >
> >
> > Hello Seong,
> > Please check the mtu on the interface on the vlan interface as well
> > as
>
> > the interface on the router to make sure that the mtu is the same.
> > ex.
>
> > sh ip
> int
> > e0, or sh ip int vlan 20.
> > Please post results.
> > Sincerely,
> > Matijevic
> > ----- Original Message -----
> > From: "seonghui" <seonghui@vads.com>
> > To: "'John Matijevic'" <matijevi@bellsouth.net>;
> > <ccielab@groupstudy.com>
> > Sent: Saturday, August 16, 2003 1:42 PM
> > Subject: RE: cat3550 cannot establish ospf nei with router/s
> >
> >
> > > Hi Matijevic,
> > >
> > > I tried that earlier, but the result is the same.
> > >
> > > regards - SH
> > >
> > > -----Original Message-----
> > > From: John Matijevic [mailto:matijevi@bellsouth.net]
> > > Sent: Sunday, August 17, 2003 1:36 AM
> > > To: seonghui; ccielab@groupstudy.com
> > > Subject: Re: cat3550 cannot establish ospf nei with router/s
> > >
> > >
> > > Hello Seong,
> > > Could you try putting ip ospf priority 0 under vlan interface on
> > > switch. Please post results. Sincerely, Matijevic
> > > ----- Original Message -----
> > > From: "seonghui" <seonghui@vads.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Saturday, August 16, 2003 1:00 PM
> > > Subject: cat3550 cannot establish ospf nei with router/s
> > >
> > >
> > > > Hi group,
> > > >
> > > > I have been 'haunted' by this problem for the past two days.
> > > > Here the problem goes...
> > > >
> > > > I have a router conneted to a Cat3550. router fa0/0 (ip address
> > > > 10.10.10.1/24) is connected to port fas0/1 (vlan 10) on cat3550.
> > > > I
> would
> > > > like cat3550 to establish ospf neighbour with the router and
> > > > hence, I created an Interface vlan 10 with ip address
> > > > 10.10.10.2/24. However,
> the
> > > > router and the cat3550 just cannot form adjacency. Below is the
> > > > debug
> > > > message:
> > > >
> > > > 07:28:30: OSPF: rcv. v:2 t:1 l:48 rid:10.10.10.1 aid:0.0.0.10
> > > > chk:7E15
> > > aut:0
> > > > auk: from Vlan10
> > > > 07:28:30: OSPF: Rcv hello from 10.10.10.1 area 11 from Vlan10
> 10.10.10.2
> > > > 07:28:30: OSPF: End of hello processing
> > > > 07:28:31: OSPF: rcv. v:2 t:2 l:32 rid:10.10.10.1 aid:0.0.0.10
> > > > chk:21B2
> > > aut:0
> > > > auk: from Vlan10
> > > > 07:28:31: OSPF: Rcv DBD from 10.10.10.1 on Vlan10 seq 0x2D3 opt
> > > > 0x42
> > flag
> > > > 0x7 len 32 mtu 1500 state EXSTART
> > > > 07:28:31: OSPF: First DBD and we are not SLAVE
> > > > 07:28:31: OSPF: Retransmitting DBD to 10.10.10.1 on Vlan10
> > > > 07:28:31: OSPF: 10.10.10.1 address 10.10.10.2 on Vlan10 is dead,
> > > > state
> > > DOWN
> > > > 07:28:31: %OSPF-5-ADJCHG: Process 1, Nbr 10.10.10.1 on Vlan10
> > > > from
> > EXSTART
> > > > to DOWN, Neighb or Down: Too many DBD retransmitions
> > > > 07:28:31: OSPF: Neighbor change Event on interface Vlan10
> > > > 07:28:36: OSPF: Rcv DBD from 10.10.10.1 on Vlan10 seq 0x2D3 opt
> > > > 0x42
> > flag
> > > > 0x7 len 32 mtu
> > > > 1500 state DOWN
> > > > 07:28:36: OSPF: Nbr state is less than INIT
> > > >
> > > > I tried running other routing protocol between the switch and
> > > > the
> > router,
> > > it
> > > > worked fine. Can some body please tell me what's the problem
> > > > with
> ospf?
> > > >
> > > > Thanks,
> > > > SH
> > > >
> > > >
> > > >
> ______________________________________________________________________
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