On 27/02/2013 03:51, Randy wrote: > *received-routes*? > If you still enable soft-reconfig-inbound on your routers(customer-facing > sessions not withstanding), you most certainly hate your routers more than > OP...;-)
it impacts memory, but if your management plane has enough memory to handle it, it's a useful debugging tool. For sure, it's the first thing I throw out if the management plane RAM runs short. SNMP polling of large router lists can work out as O(n^2) CPU usage if the router stores the polled objects as linked lists or in some cases, in tree structures. This is because snmpgetnext cannot maintain a pointer to the next object, which in some situations will mean a complete tree walk operation. So your CPU requirements will scale according to (size of structure) * (average number of complete walks through the structure). If you're using linked lists, or have a naive tree implementation, "average number of complete walks through the structure" = "size of structure" / 2 for a full tree walk. I.e. you can require (n^2)/2 complete runs through the structure in order to run a full snmp dump. Obviously this isn't always the case, but there are some well known examples of where it happens. For all its faults, soft-reconfig-inbound only adds O(N) to RAM requirements and almost nothing to CPU. Nick > ./Randy > > --- On Tue, 2/26/13, Nick Hilliard <[email protected]> wrote: > >> From: Nick Hilliard <[email protected]> >> Subject: Re: BGP RIB Collection >> To: "chip" <[email protected]> >> Cc: "North American Network Operators Group" <[email protected]> >> Date: Tuesday, February 26, 2013, 11:21 AM >> On 26/02/2013 17:24, chip wrote: >>> Currently I'm gathering this data via SNMP. >> >> whoa, you must really hate your router to do that to it. >> >>> While this works it has its draw backs, it >>> takes approximately 20 minutes per view, its nowhere >> near real-time, and >>> I'm unable to gather information for IPv6. SNMP, >> however, is faster than >>> screen scraping. All of the XML based access >> methods seem to take about >>> the same time as well. >> >> cisco: >> -- >> term len 0 >> show bgp ipv4 unicast neigh x.y.z.w received-routes >> -- >> >> juniper: >> -- >> show route receive-protocol bgp x.y.z.w | no-more >> -- >> >> Easily scriptable using rancid or something similar. >> Of course, this sucks >> because you're only seeing the route summary, not any of the >> attributes. >> >>> project is still in its infancy. BMP seems to be >> a good solution but I've >>> not found a working client implementation yet. I >> see that you can actually >>> configure this on some Juniper gear but I can't seem to >> locate a client to >>> ingest the data the router produces. >> >> Can you provide a list of the clients that you have >> tried? It would save >> people the effort of going through them and finding out the >> same things as >> you did. >> >> Nick >> >> >> >> >
