Connecting Bay to Cisco ( WAN wise )
John L. Repucci
I have to connect a Bay router ( BCN, v11.01/1 ) at my end to a Cisco 3000
at another company and we have had little luck so far getting them to talk.
They wanted to go with HDLC, but as far as I can tell, the Bay's do not
support that and of course the Cisco's do not support Bay Standard. We
have tried PPP without success so far.
The sync ports are up on both sides, but ip protocol is down on both ends.
What WAN protocol works best between both routers? Any hints or FAQs that
I should be reading?
Thanks,
John Repucci
Guidant Corp
John L. Repucci
I have been able to get the two routers to talk via IP, but now I have the
following warning message in the log:
# 24: 03/12/98 08:06:24.160 WARNING SLOT 1 PPP Code:
9
Circuit 9 rejecting packet - larger than MTU size.
# 25: 03/12/98 08:06:49.464 WARNING SLOT 1 PPP Code:
0
The previous event on slot 1 repeated 2630 time(s). [Code 9]
( The Bay router is not happy ! )
The MTUs on both sides are set to 1500. If I increase the Bay MTU to
either 1600 or 1700, then we no longer get the message. Also, when I ping
the cisco with a packet size of greater than 1492, the ping stalls. Less
than or equal to 1492, the cisco responses right away.
Any thoughts on the cause of the MTU issue? Should both MTUs be set the
same?
Thanks,
John Repucci
Guidant Corp.
( Note: we both have open cases with Bay and Cisco and so far they have not
supplied us with an answer. )
Chris Antonucci
John L. Repucci wrote:
>
> I have been able to get the two routers to talk via IP, but now I have the
> following warning message in the log:
>
> # 24: 03/12/98 08:06:24.160 WARNING SLOT 1 PPP Code:
> 9
> Circuit 9 rejecting packet - larger than MTU size.
>
> # 25: 03/12/98 08:06:49.464 WARNING SLOT 1 PPP Code:
> 0
> The previous event on slot 1 repeated 2630 time(s). [Code 9]
>
> ( The Bay router is not happy ! )
John,
If the Bay box is dumping the packet, the total transmit packet size
must
be larger than 1500 (this does happen with payload plus PPP packet
header).
What might be happening is that the node that is transmitting the PING
may
be setting the 'Don't Fragment' bit. I've seen this happen with the
current
SUN O/S's (it doesn't make much sense, but they're setting it). The
packet is
too large to fit within the packet size window and yet the router can't
fragment it. Therefore it drops it.
> The MTUs on both sides are set to 1500. If I increase the Bay MTU to
> either 1600 or 1700, then we no longer get the message. Also, when I ping
> the cisco with a packet size of greater than 1492, the ping stalls. Less
> than or equal to 1492, the cisco responses right away.
MRU (and MRRU in multilink PPP) values are set to the remote peer during
link
negogiation stage (LCP). One peer tells the other the largest packet
that
it can receive. Since the peer is informed of the remote maximum value,
it
shouldn't matter what the value is set to.
> Any thoughts on the cause of the MTU issue? Should both MTUs be set the
> same?
The above comment notwithstanding, I believe that the PPP implementation
in
the Bay router is looking for symmetrical values of MTU/MRU for each
link.
You would probably be best off setting the MRU values on the Bay and
Cisco
boxes to 1600 to reduce/eliminate packet fragmentation issues (at least
if
you are runnning e-net).
Hope this helps.
-cna
> Thanks,
>
> John Repucci
> Guidant Corp.
>
> ( Note: we both have open cases with Bay and Cisco and so far they have not
> supplied us with an answer. )
--
(I only test the annex software; I don't support it.
Please direct inquiries to sup...@xylogics.com.)
--
Chris Antonucci <Chris_A...@Baynetworks.com> Tel#: 978-670-8888
RASD S/W Quality Assurance Bay Networks 800-222-7611
--
ospa...@dra.hmg.gb
I have a problem with Bay (BCN) to Cisco in slow ftp when getting from
the Bay site to the Cisco site FTP transfer is 1/2k. When putting a file
from Cisco site to Bay site transfer is line speed. Cisco to Cisco is
fine. Changing MTU value (ON/OFF) on Bay seems to have no effect. On
Cisco IP MTU value does have an effect which is why I belive this to be
the problem. Seems MTU on Bay is set for 4608 and IP MTU on Cisco 800
(512k line).Bay running ver 9.0 s/ware. Any idea?
Thanks
Owen