Hi, I've been wondering for a while whether "just enabling jumbo frames on all L2 ports in our network" will have adverse effects.
Or, phrased differently, why do vendors bother with not havining
jumbo-on-by-default on L2 ports? After all, having a too-big *L2* MTU
will not magically cause large packets to appear - they need to come
from a L3 interface somewhere, and if all L3 interfaces are at 1500,
bigger L2 MTUs will not have an effect.
Or - will they? So, if I go to a "switchport" and configure
interface gig4/4
switchport
mtu 9216
what exactly will be changed "under the hood"? Will it change things
like buffer allocation ("all buffers are always allocated at 9216 bytes
now"), possibly leading to packet drops due to less available buffers,
etc.? Or will it just set some magic bit "do not drop oversized frames
going out there"?
This is specifically talking about cat6500 with sup2 or sup720 architecture,
but the general questions "why do vendors not ship large-mtu on L2-ports
by default, what is the drawback?" remains.
Am I making sense?
gert
--
USENET is *not* the non-clickable part of WWW!
//www.muc.de/~gert/
Gert Doering - Munich, Germany [email protected]
fax: +49-89-35655025 [email protected]
pgpPXUg7XJLWq.pgp
Description: PGP signature
_______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
