Enterasys Networks 700 - Manual (Page 68)

The MultiSwitch 700 Device View
2-48 Managing the Module
5. Click Add to add the redirect pair you have just configured to the list. The new
entry will now be displayed in the Current Active Entries list in this window and
the port traffic will begin to be redirected.
To delete an entry:
1. Click to highlight the entry line in the Current Active Entries list that you wish
to delete.
2. Click Delete to remove the redirect pair you have highlighted from the Current
Active Entries list. The entry will be deleted from the Current Active Entries list
and the traffic from the source port will not be redirected to the destination
port any longer.
Priority Configuration
The MultiSwitch 700 modules support priority packet forwarding. Priority packet
forwarding lets you designate certain packets to be of higher importance than
others, thereby allowing for the forwarding of these packets before packets of
lower priority. This functionality is essential for time-critical applications — such
as real-time video — on shared networks.
Frame priority is enabled by the “tagging” of MAC frames so that they are given a
priority designation when they are forwarded by the MultiSwitch 700 module —
which is a tag-aware switch (i.e., one that adheres to the IEEE P802.1p and IEEE
P802.1q Draft Standards). Tagging a frame is accomplished by adding a Tag
Header to a frame immediately following its original Destination and Source
MAC address fields (and any routing fields, if present), and then recomputing the
Frame Check Sequence (FCS) appropriately. On receiving such a frame, a
tag-aware switch will read the priority from the tagged portion of the frame,
remove the Tag Header, recompute the FCS, and then direct it to its appropriate
transmission queue.
There are eight priority levels — indicated 0 through 7— available to designate
user priority. Frames tagged with a 0 represent the lowest priority level (or
normal) traffic, and frames tagged with a 7 indicate the highest priority level
traffic.
The MultiSwitch 700 module itself supports two transmission queues: one that is
for 0 or normal priority traffic (or any non-tagged traffic), and a second queue that
is reserved for frames that have been tagged with a priority level of 1 or higher.
On receiving any priority-tagged frames, the MultiSwitch 700 will forward them
out of the high priority queue before forwarding any frames in the normal
NOTE
The Priority Configuration menu option will only appear in the Device menu for
modules that respond to any of NetSight Element Manager’s queries to the following
OIDs: ctPriorityExtPortStatus, ctPriorityExtMaxNumMACEntries, or
ctPriorityExtNumPktTypeEntries
. If your module’s firmware does not respond to
these queries, contact the Global Call Center for firmware upgrade information.