Understanding topologies

binarysoul

When I see a network topology, I get confused, especially when trying to solve a problem and find out where the fault might be. I'm not talking about a small network, but one that includes many routers, private and public IPs, HRSP addresses, firewalls, telco equipment, WAN, VPN, servers and so on. It gets too overwhelming.

Here is a simple example:




Have you had this problem? How should I approach this? I'm good at analyzing things and pinpointing to problems, but this area is new to me. Any ideas folks?
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Smallguy

the only thing I've ever found that helps me is to break down the problem in smaller portions till you isolate the problem to something easier to trouble shoot

prove or dis prove connectivity and work from there


the mroe you know the easier the issue becomes

dtlokee

This is where the OSI layers can help. Think of the network in terms of L2 connectivity and then L3 connectivity. That helps break the complexity down. For example when looking at a L3 diagram of a network we usually don't pay attention to the path through all the switches between the routers and L3 switches. It is an important concept, but as long as we have L2 connectivity we don't really care about it. Likewise when troubleshooting a problem we typically use ping, that tests connectivity to L3. The net step may be to test an application layer protocol (like telnet or http) or if ping fails, look at possble L3, L2, or L1 problems.