path analysis on CW2000

[glmrenard]

Hello,

How can I obtain a leyer 2 path analysis instead of a layer 3. All my switches are visible on topology view.

I hav the latest patches isntalled and all seem OK so ... Why have I a layer3 ?

Thanks in advance,

Guillaume

[rmushtaq · Accepted solution]

Layer 3 Paths are always displayed. Layer 2 paths are displayed only where they exist and where they can be determined.

In general, the Layer 2 path is the physical path on the network that packets follow through Cisco devices. Path Analysis cannot always determine the Layer 2 path for every Layer 3 hop.

The Layer 2 path includes devices that are either SNMP accessible and known through Topology Services, or are SNMP inaccessible but have been discovered by User Tracking (for example, end-user hosts).

Path Analysis supports Layer 2 tracing on Ethernet, Fast Ethernet, Gigabit Ethernet, and LANE networks. LANE support includes tracing on the path inside an ATM cloud. For this release, Path Analysis Layer 2 tracing does not support FDDI, Token Ring, and WAN interfaces, or router bridge groups.

http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/cw2000/camp_mgr/camp_3x/cmgr_3_2/u_guide/path.htm

[glmrenard]

Hello,

Thanks a lot for your answer. It's not what I expected but... Now I know.

Guillaume

[b.smeets]

There are more constraints to Path Analysis. An important one: to get a Layer 2 trace, the source (start object) cannot be an end host but must be a Cisco device, and source and destination must be within the managed domain (see the docs). Also, layer 2 traces over WAN links don't work. And if you have two routers using HSRP, a layer 2 trace across these routers will only work in the latest release of Campus Manager (see Release Notes).

The docs also say your routers should do source routing and your mapping of VLANs to IP subnets should be correct, but at our place PA works OK even if this is not the case.