Graphing Vlan's

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opt8low
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Joined: Tue Apr 18, 2006 8:49 am

Graphing Vlan's

Post by opt8low »

I am having trouble with graphing Vlan's. I have searched and can't seem to find an answer. All I see when searching is the question asked about graphing Vlan's with no answers. I am hoping that someone has figured it out and can pass that on.

I have multiple switches from multiple makers and when I do an SNMP walk I see the vlans. I can create a graph for them but get no data for the graphs. Am I missing something? Has Cacti ever graphed Vlans?

Any help would be greatly appreaciated,


Dana
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Howie
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Post by Howie »

If you mean vlan IP interfaces, then quite a few switches will show little/no info here as they only count data that the CPU processes - some Cisco Catalyst and Extreme at least have this issue. On some/most L3 switch architectures the first packet hits the CPU which sets up a switching path in the ASICs for any following packets, so it doesn't 'see' them. I have had this trouble with Extreme Blackdiamond and Cisco 3750s before now.

Cacti will graph anything that you can get from SNMP, but if the switch doesn't record the data, then Cacti can't help you.
Weathermap 0.98a is out! & QuickTree 1.0. Superlinks is over there now (and built-in to Cacti 1.x).
Some Other Cacti tweaks, including strip-graphs, icons and snmp/netflow stuff.
(Let me know if you have UK DevOps or Network Ops opportunities, too!)
opt8low
Posts: 7
Joined: Tue Apr 18, 2006 8:49 am

Graphing Vlan's

Post by opt8low »

I was hoping to just graph vlan's. They don't have IP's on them. Most of vlan's that I want to graph are Tagged with 802.1Q tagging. I would take any type of graphing for vlan's though. The switches I am trying to use this on are Extreme X250E and 450E's.

When I do the SNMP walk I see the Vlan's. I will attach a picture of what that looks like. I create the graph, but get no data.... Any ideas? Or will I have to go back to Extreme and start talkig to them about there MIB's?


Thanks,

Dana
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nyx
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Post by nyx »

I am not sure about the switches you are using but I noticed something else that might be a issue for you.

Switches dont broadcast, the reason I bring that up is, you say that the VLANs you are graphing do not have IP's on them. If that is the case, even if you get the graph working, you wont see ALL the data.

As there is no routing happening if there is no IP... if you graph the vlan interface on a switch, the packets might just get switched directly out the physical interface asic's and never hit the VLAN interface. If it was a "router" for the network, you would see all the data leaving that network. However, in some cases, even with a IP on a vlan, and it being a default route for that network... you wont always see all the data...

I think you will be better looking at the "aggregate" plugin, and add all the physical interfaces in each vlan together. This is what I have done in a few places...



:)
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Howie
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Post by Howie »

The rif and VLAN interfaces on our old Summit48s (dead now) and BD6808 with EW 4.x,6.x and 7.x don't show useful data. Maybe it's changed in XOS, but those 3 have never been useful for this, and I have never had a good answer from TAC.

There's more discussion of some ExtremeWare-related stuff here.

Here's a recent discussion about the same kinds of problems on Cisco switches, too, on the excellent c-nsp mailing list.
Weathermap 0.98a is out! & QuickTree 1.0. Superlinks is over there now (and built-in to Cacti 1.x).
Some Other Cacti tweaks, including strip-graphs, icons and snmp/netflow stuff.
(Let me know if you have UK DevOps or Network Ops opportunities, too!)
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