Depends.
Without distributed forwarding, some part of the packet will always
transit the bus. What part depends on the makeup of the box. Either
way only ONE of the PFC's on the Sup is used.
If all of the cards in the box are fabric-enabled, then the system will
go into compressed mode which give you the possibility of 30Mpps. What
happens here is the LC takes the packet in, and just forwards the header
to the PFC on the Sup2. The PFC makes the decision and informs the
originating LC who then uses the fabric to transit the packet to the
egress line card. If the egress line card is the same as the ingress
line card (and the packet is unicast) then the packet does not transit
the fabric, but is locally switched on the card (the header still needs
to go to the PFC regardless since we don't have a DFC).
If any of the cards in the box are not fabric-enabled, then the system
will remain in normal mode, you have a theoretical max of 15Mpps, and
the packets fully transit the bus. At which point your fabric is
useless. (If on the other hand you just add DFC's to the fabric-enabled
cards then things are happy again. You will still only get 15Mpps out
of the Sup, but now the only packets that even transit the original bus
are one that ingress/egress from non-fabric cards.)
David
-----Original Message-----
From: Rubens Kuhl Jr. [mailto:rkuhljr@uol.com.br]
Sent: Monday, April 16, 2001 4:31 PM
To: cisco-nsp@puck.nether.net
Subject: [nsp] Fabric-enabled cards on Cat6500/C7600
On a Catalyst 6500(or C7600) ,with Supervisor 2 and one switch-fabric
module, what path(s) will be used by 6516* fabric-enabled-gigabit cards
, no
DFC, to forward frames ?
( ) switch-fabric only
( ) switch-fabric (main) and bus, active-standby, only one path active
( ) switch-fabric and bus, active-active, both paths used even with low
loads
( ) switch-fabric (main) and bus, active-active, both paths used if load
exceeds threshold
Rubens Kuhl Jr.
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:35 EDT