Trunk Vlan Filtering; Span Traffic; Span And Rspan Session Limits - Cisco WS-X6066-SLB-APC - Content Switching Module Software Manual

SPAN and RSPAN Session Limits

Trunk VLAN Filtering

Trunk VLAN filtering is analysis of network traffic on a selected set of VLANs on trunk source ports.
You can combine trunk VLAN filtering with other source ports that belong to any of the selected
VLANs, and you can also use trunk VLAN filtering for RSPAN. Based on the traffic type (ingress,
egress, or both), SPAN sends a copy of the network traffic in the selected VLANs to the destination port.
Use trunk VLAN filtering only with trunk source ports. If you combine trunk VLAN filtering with other
source ports that belong to VLANs not included in the selected list of filter VLANs, SPAN includes only
the ports that belong to one or more of the selected VLANs in the operational sources.
When a VLAN is cleared, it is removed from the VLAN filter list. A SPAN session is disabled if the
VLAN filter list becomes empty.
Trunk VLAN filtering is not applicable to VSPAN sessions.

SPAN Traffic

All network traffic, including the multicast and bridge protocol data unit (BPDU) packets, can be monitored
using SPAN (RSPAN does not support monitoring of BPDU packets or Layer 2 protocol packets such as
CDP, DTP, and VTP). Multicast packet monitoring is enabled by default.
In some SPAN configurations, multiple copies of the same source packet are sent to the SPAN
destination port. For example, a bidirectional (both ingress and egress) SPAN session is configured for
sources a1 and a2 to a destination port d1. If a packet enters the switch through a1 and gets switched to
a2, both incoming and outgoing packets are sent to destination port d1; both packets would be the same
(if a Layer-3 rewrite occurs, the packets are different). Similarly, for RSPAN sessions with sources
distributed in multiple switches, the destination ports might forward multiple copies of the same packet.
SPAN and RSPAN Session Limits
You can configure (and store in NVRAM) a maximum of 30 SPAN sessions in a Catalyst 6000 family
switch. See
multiple ports or VLANs as sources for each session.
Table 38-1 SPAN and RSPAN Session Limits
SPAN/RSPAN Sessions
rx or both SPAN sessions
tx SPAN sessions
tx, rx, or both RSPAN source sessions
RSPAN destinations
Total SPAN sessions
1. When an RSPAN source session is configured, it will reduce the limit for rx or both SPAN sessions by one.
2. 2 rx or both SPAN sessions + 4 tx SPAN sessions + 24 RSPAN destination sessions = 30 total SPAN sessions.
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
38-4
Table 38-1 for the supported combinations of SPAN/RSPAN sessions. You can configure
Chapter 38 Configuring SPAN and RSPAN
Catalyst 6000 Family Switches
2
4
1
24
2
30
1
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