Concept Guide

This phenomenon occurs where trac is terminated on the switch. Trac has not originated from the switch and is not transiting the
switch.
The switch accepts all trac destined to the switch, which is received on management or front-end data port. Response trac with
management port IP address as source IP address is handled in the same manner as switch originated trac.
Switch-Originated Trac
This phenomenon occurs where trac is originating from the switch.
1 Management Applications (Applications that are congured as management applications):
The management port is an egress port for management applications. If the management port is down or the destination is not
reachable through the management port (next hop ARP is not resolved, and so on), and if the destination is reachable through a data
port, then the management application trac is sent out through the front-end data port. This fallback mechanism is required.
2 Non-Management Applications (Applications that are not congured as management applications as dened by this feature):
Non-management application trac exits out of either front-end data port or management port based on routing table. If there is a
default route on both the management and front-end data port, the default for the data port is preferred route.
Behavior of Various Applications for Switch-Initiated Trac
This section describes the dierent system behaviors that occur when trac is originating from the switch:
EIS Behavior: If the destination TCP/UDP port matches a congured management application, a route lookup is done in the EIS table and
the management port gets selected as the egress port. If management port is down or the route lookup fails, packets are dropped.
EIS Behavior for ICMP: ICMP packets do not have TCP/UDP ports. To do an EIS route lookup for ICMP-based applications (ping and
traceroute) using the source ip option, the management port IP address should be specied as the source IP address. If management port
is down or route lookup fails, packets are dropped.
Default Behavior: Route lookup is done in the default routing table and appropriate egress port is selected.
Table 38. Behavior of Various Applications for Switch-Initiated
Trac
Protocol Behavior when EIS is Enabled Behavior when EIS is Disabled
dns EIS Behavior Default Behavior
ftp EIS Behavior Default Behavior
ntp EIS Behavior Default Behavior
radius EIS Behavior Default Behavior
Sow-collector Default Behavior
Snmp (SNMP Mib response and SNMP
Traps)
EIS Behavior Default Behavior
ssh EIS Behavior Default Behavior
syslog EIS Behavior Default Behavior
tacacs EIS Behavior Default Behavior
Internet Group Management Protocol (IGMP) 403