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Home > Archive > CCNP > March 2003 > mixing 100mb and gb trunks
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mixing 100mb and gb trunks
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| darthfeces 2003-03-08, 10:13 pm |
| i'd like to ask a switching question.
we have a switch fabric of
2 6500's in the core
mffc's on each
and gb and 100mb line cards.
we have 20 2820's 100mb trunk
20 cat5000's 100mb trunk
and we are integrating
some 3548's
and 82 3550's
at gb to the core.
are there any potential issues with mixing 100/mb and 1000/mb trunks in the network without pruning ?
i have been noticing that cat5000's see a lot of in-discards
when i looked it up it seemed to say that they are frames that could not be switched.
also on some100/mb trunks off a 3548 i see giants and input errors.
the gb trunks show no problems.
could the 100mb be "choke points" until we go all gb ?
thanks. | |
| anchor40 2003-03-12, 9:06 am |
| What is the utilization of those 100MB trunks? We've got a mix of GigE and 4GigEChannel trunks in our core, and don't have that problem, but then again, we're not "pushing" the network, by any stretch.
If you are pushing the limits of the 100MB trunks, are you able to create FastEChannel into the Core?
Your post doesn't describe how your network is layed out but it sounds like you might be connecting your Access layer straight into your Core. But as always, a picture is worth a thousand words!
Good Luck!
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| SureshHomepage 2003-03-15, 12:56 am |
| Check these two points which often useful in sorting out the issue.
1. Lock to 100 meg & full duplex on both the 100Mb trunk ports.
2. Toggle between the encap to ISL or dot1q.
ISL adds 30bytes to each frame where as dot1q adds 4 bytes. Ethernet frames cannot exceed 1500 bytes, so this additional VLAN tagging information would make the frame to be large. Frames that exceed the 1500 bytes limit are 'baby giant frames'. Switch will usually report these frames as Ethernet errors or oversize frames.
I have the same setup at couple of my client networks. They are going good we mix the 100FX using the 100FX MT-RJ blades and the Gig blades using the 1000SX GBICs. All in MM fibre we never faced any such issue.
A quick questions how about the backplane cap of the 6500? |
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