No Enterprise Device Manager Access To A Switch; How To Stop Icmp Redirects From Causing High Cpu Utilization; Resolution - Avaya 8800 Troubleshooting Manual

Software troubleshooting

No Enterprise Device Manager access to a switch

If the switch and the PC running the Web browser are in the same network, you may find that
even though other applications (such as Telnet) can access a particular switch, the Enterprise
Device Manager cannot. This situation can occur if the Web browser has a proxy server that
resolves the www path and returns the reachable IP address to the browser. If there is no route
from the proxy server to the switch, the http query does not reach the switch, and there is no
response.
To prevent this problem, make sure that if your Web browser uses a proxy server, a route is
specified from the proxy server to the switch.
How to stop ICMP redirects from causing high CPU
utilization
If the switch experiences CPU utilization up to 100% due to processing of redirects at a rate
of over 500 per second, there are multiple potential causes, depending on your network
topology:
• Hosts can send packets to the 8800/8600 VLAN destined for networks beyond the same
VLAN firewalls and routers.
• Hosts, servers, routers, firewalls, and the 8800/8600 VLAN can all be on the same VLAN
in a legacy network design.
• Hosts and servers can constantly send packets to networks beyond firewalls and
gateways.
• Hosts and servers can use the 8800/8600 VLAN address as their default gateway.
In all the above cases, each packet reaching the 8800/8600 destined for other networks causes
an ICMP redirect, which the CPU must process.

Resolution

To resolve this issue, enable ICMP redirect. With ICMP redirect enabled, the 8800/8600 switch
sends redirect messages to any host sending packets to other networks. The redirect message
includes the destination host address and its proper next-hop router.
Enable ICMP redirect:
icmp-redirect-msg enable (CLI)
OR
76 Troubleshooting
Comments? infodev@avaya.com
July 2013