[j-nsp] L2 mismatch timeouts...

Eric Van Tol eric at atlantech.net
Sat Mar 12 10:29:21 EST 2005


It is possible that these L2 mismatch timeouts are due to the HP VLAN1.
If HP uses a VLAN tag for VLAN1, then this would occur, as Junipers have
no concept of "tagged" VLANs.

We see similar mismatch timeouts on our M-series routers that are
connected to Cisco switches via an 802.1q trunk.

-evt 

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net
[mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Zvezdelin
Vladov
Sent: Saturday, March 12, 2005 3:45 AM
To: Phil Jolliffe; juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] L2 mismatch timeouts...

Hello Phil,

What could be the cause of those kind of malformed
or short frames?

Wouldn't they be counted as CRC/Align or whatever
other error counters are available on the LINK layer?

Why all the other L2 counters for errors are zero?

I made some tests with another pic - 4x F/E 100 BASE-TX,
and I have the same results.... L2 mismatch timeouts.

I did change the switch - from HP to Cisco 2950 I
see the same problems with both of the PICs.

The very strange thing is that on a GE IQ SFP-with SFP-LX
port I don't see anything like this. The switch in this
case is cisco 3750.

And now comes the VERY strange part - 
when I turned off the VLAN tagging on the juniper -
and made the cisco switch switchport access vlan X,
[i.e. cisco adds the VLAN tag] the problem on the
Juniper disappeared!
I.e. no single L2 mismatch timeout!

Thank you,

Zvezdelin Vladov


On Fri, 11 Mar 2005 17:37:06 -0800, Phil Jolliffe <pjolliff at juniper.net>
wrote:
> L2 mismatch timeouts is a count of malformed or short packets that
cause
> the incoming packet handler to discard the frame as unreadable.
> 
> Unknown L2 formats (CDP, IPX, or even inet/inet6/mpls/iso if the
family
> statement is not under the interface unit) show up as the policed
> discard counter incrementing.
> 
> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net
> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of daniel
> Sent: Saturday, March 12, 2005 12:40 AM
> To: Zvezdelin Vladov
> Cc: juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] L2 mismatch timeouts...
> 
> Zvezdelin,
> 
> if the link runs clean (run a rapid ping, large packet size, various
> payloads to get some additional confirmation), i'd suspect the HP is
> still sending some type of unsupported L2 protocol to the router.
> Perhaps the switch can do port- mirroring so you can do some sniffing
?
> 
> Daniel.
> 
> On 10:26 Wed 09 Mar     , Zvezdelin Vladov wrote:
> > Dear All,
> >
> > I see L2 mismatch timeouts between m7i, 7.1R1.3, with this pic : 2x
> > F/E, 100 BASE-TX and HP2524 with:
> >  Firmware revision  : F.05.22
> >   ROM Version        : F.02.01
> >
> > On the HP, I have turned off spanning tree, cdp, on the port where
the
> 
> > juniper is connected.
> > At the port where juniper is connected, I have only one VLAN- and
this
> 
> > VLAN is turned on the juniper too.
> > I have set full-duplex 100mbits both on the Juniper and the HP.
> > I see no errors on the HP side, but see those L2 mismatch timeouts,
> > nomatter what I do.
> > I have chaned cables - with no effect.
> > The port is not loaded... it doesn't go even close to 512Kbit/s.
> >
> > Any ideas on what might be the cause and how to fix it?
> >
> > Thank you,
> >
> > Zvezdelin Vladov
> >
> > P.S. Here is dump of sho interfaces fe-1/3/0 extensive
> >
> > Physical interface: fe-1/3/0, Enabled, Physical link is Up
> >   Interface index: 148, SNMP ifIndex: 75, Generation: 31
> >   Link-level type: Ethernet, MTU: 1518, Speed: 100mbps, Loopback:
> Disabled,
> >   Source filtering: Disabled, Flow control: Disabled
> >   Device flags   : Present Running
> >   Interface flags: SNMP-Traps 16384
> >   Link flags     : None
> >   CoS queues     : 4 supported
> >   Hold-times     : Up 0 ms, Down 0 ms
> >   Current address: 00:12:1e:1c:24:db, Hardware address:
> 00:12:1e:1c:24:db
> >   Last flapped   : 2005-03-07 18:29:32 EET (1d 15:55 ago)
> >   Statistics last cleared: 2005-03-09 10:01:49 EET (00:23:22 ago)
> >   Traffic statistics:
> >    Input  bytes  :              1299356                 4168 bps
> >    Output bytes  :              1302889                 4936 bps
> >    Input  packets:                 3905                    6 pps
> >    Output packets:                 3756                    4 pps
> >   Input errors:
> >     Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed
> discards: 0,
> >     L3 incompletes: 1, L2 channel errors: 0, L2 mismatch timeouts:
> > 702, FIFO errors: 0,
> >     Resource errors: 0
> >   Output errors:
> >     Carrier transitions: 0, Errors: 0, Drops: 0, Collisions: 0, Aged
> packets: 0,
> >     FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource
> errors: 0
> >   Queue counters:       Queued packets  Transmitted packets
> Dropped packets
> >     0 best-effort                 3716                 3716
> 0
> >     1 expedited-fo                   0                    0
> 0
> >     2 assured-forw                   0                    0
> 0
> >     3 network-cont                  48                   48
> 0
> >   Active alarms  : None
> >   Active defects : None
> >   MAC statistics:                      Receive         Transmit
> >     Total octets                       1436592          1319553
> >     Total packets                         4598             3755
> >     Unicast packets                       3664             3755
> >     Broadcast packets                      233                0
> >     Multicast packets                      701                0
> >     CRC/Align errors                         0                0
> >     FIFO errors                              0                0
> >     MAC control frames                       0                0
> >     MAC pause frames                         0                0
> >     Oversized frames                         0
> >     Jabber frames                            0
> >     Fragment frames                          0
> >     VLAN tagged frames                       0
> >     Code violations                          0
> >   Filter statistics:
> >     Input packet count                    4598
> >     Input packet rejects                     0
> >     Input DA rejects                       702
> >     Input SA rejects                         0
> >     Output packet count                                    3755
> >     Output packet pad count                                   0
> >     Output packet error count                                 0
> >     CAM destination filters: 1, CAM source filters: 0
> >   Autonegotiation information:
> >     Negotiation status: Incomplete
> >   Packet Forwarding Engine configuration:
> >     Destination slot: 1
> >     CoS transmit queue               Bandwidth               Buffer
> > Priority   Limit
> >                               %            bps     %          bytes
> >     0 best-effort            95       95000000    95              0
> >   low    none
> >     3 network-control         5        5000000     5              0
> >   low    none
> >
> >   Logical interface fe-1/3/0.0 (Index 69) (SNMP ifIndex 78)
> (Generation 7)
> >     Flags: SNMP-Traps 16384 VLAN-Tag [ 0x8100.503 ]  Encapsulation:
> ENET2
> >     Traffic statistics:
> >      Input  bytes  :              1298900
> >      Output bytes  :               339949
> >      Input  packets:                 3899
> >      Output packets:                 2472
> >     Local statistics:
> >      Input  bytes  :              1257220
> >      Output bytes  :               339949
> >      Input  packets:                 3844
> >      Output packets:                 2472
> >     Transit statistics:
> >      Input  bytes  :                41680                  408 bps
> >      Output bytes  :                    0                    0 bps
> >      Input  packets:                   55                    1 pps
> >      Output packets:                    0                    0 pps
> >     Protocol inet, MTU: 1500, Generation: 14, Route table: 0
> >       Flags: None
> >       Addresses, Flags: Preferred Is-Preferred Is-Primary
> >         Destination: x.x.x.x, Local: x.x.x.x, Broadcast: x.x.x.x,
> >         Generation: 12
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > http://puck.nether.net/mailman/listinfo/juniper-nsp
> _______________________________________________
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