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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 67 Configuring ERSPAN
Information About ERSPAN
Restrictions for ERSPAN
The following restrictions apply for this feature:
•
The maximum number of available ports for each ERSPAN session is 128.
•
A maximum of 8 ingress and 8 egress ERSPAN sessions (a total of 16 sessions) are supported.
•
You can configure either a list of ports or a list of VLANs as a source, but cannot configure both for
a given session.
•
When a session is configured through the ERSPAN CLI, the session ID and the session type cannot
be changed. To change them, you must use the
no
form of the configuration commands to remove
the session and then reconfigure the session.
•
ERSPAN source sessions do not copy locally-sourced Remote SPAN (RSPAN) VLAN traffic from
source trunk ports that carry RSPAN VLANs.
•
ERSPAN source sessions do not copy locally-sourced ERSPAN GRE-encapsulated traffic from
source ports.
The Catalyst 4500 series switches do not support the following for this feature:
•
ERSPAN destination type.
•
Timestamp indication in the ERSPAN header.
•
Bad/Short/Oversized (BSO) packet indication in the ERSPAN header.
•
The original VLAN ID or Class of Service (COS) in the ERSPAN header.
•
Generic routing encapsulation (GRE) header flags.
•
GRE header sequence number or key.
•
Maximum transmission unit (MTU) checking and fragmentation. Hence, traffic exceeding the
configured MTU size (as determined by Layer 3 protocols) is dropped.
•
Truncation of the original packet; because of which the T-bit in the ERSPAN header is always zero.
•
Setting of the Differentiated Services Code Point (DSCP)/Time to Live (TTL) field for IP
encapsulation differently for various ERSPAN source sessions. Use the
erspan
{
ttl
|
tos
} command
to set these values. The configured values are used in all ERSPAN source sessions originating from
the device.
•
Simple Network Management Protocol (SNMP).
Information About ERSPAN
•
•
ERSPAN Overview
The Cisco ERSPAN feature allows you to monitor traffic on ports or VLANs, and send the monitored
traffic to destination ports. ERSPAN sends traffic to a network analyzer, such as a Switch Probe device
or a Remote Monitoring (RMON) probe. ERSPAN supports source ports, source VLANs, and
destination ports on different devices, which helps remote monitoring of multiple devices across a
network.
Summary of Contents for Catalyst 4500 Series
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