I should have mentioned that I'm only getting a default route from my upstream providers. I guess I could request a full table, as we have enough resources to handle it on the edge routers. In the past there has not been a convincing reason to receive a full bgp route table.
Just curious, how large,in megabytes, is the current bgp table? JB > On Mar 2, 2015, at 5:11 PM, Clint Wade <[email protected]> wrote: > > Everything I'm stating below here is under the assumption you're receiving a > full route table from the ISP's and not just a default route. If all you're > getting is a default, you're looking at something like policy based routing > or possibly PFR to fix this as far as I know. > > Weight and Local Pref to affect outbound --> You'll want it higher on the one > you want to be the exit point and as long as you have an iBGP connection > between your two BGP edge routers you'll be ok. If no iBGP link between your > two edge routers exists then affecting outbound is impossible as you're > limited by OSPF and the best you can do is force one to be the outbound for > all prefixes. Another way I've seen done what you're doing is to originate 1 > default in OSPF as Type 1 and the other as Type 2, obviously the exit path to > the Type 1 route is preferred, but once it makes it to that edge router > you'll have to rely on BGP path selection to affect which edge router to > egress for specific prefixes, which is why the iBGP link is required. > > AS Path and MED to affect inbound --> Usually done by sending communities to > your providers to affect their routes; Each provider has a list of > communities they accept to perform functions such as 'Add 4x AS# to existing > AS_Path' or 'Set local pref' on the provider side. You'll need to use a > looking glass server to verify these changes, and you'll want to check them > from a couple different providers looking glass to see what effects it has on > routing outside of the provider you're trying to traffic engineer. Keep in > mind you have to be careful as some providers transit to other provider > connections can get saturated which can lead to some unexpected side affects, > so you'll have to keep a close eye on performance (latency, etc.) > >> On Mon, Mar 2, 2015 at 4:12 PM, Aaron <[email protected]> wrote: >> I also have 2 (working on 3) Internet connections and only learn default >> route from upstream provider.... >> >> I don’t know if this is best/common practice but if I ever prefer a /32 to >> exit out one of my particular internet connections, I'll point a static /32 >> out that internet connection and redistribute it into my igp....my igp >> happens to be mb-ibgp for my l3vpn's to rcv it across my mpls network. >> >> Aaron >> >> -----Original Message----- >> From: cisco-nsp [mailto:[email protected]] On Behalf Of CWO >> Network Operations >> Sent: Monday, March 02, 2015 3:40 PM >> To: [email protected] >> Subject: [c-nsp] OSPF and BGP relationship >> >> I have a question about the common practice of using OSPF and (i)bgp. >> >> Here is my setup: >> >> >> I have 4 Cisco routers (A, B, C & D). All routers are connected to each >> other through metro ethernet connections. The 4 routers have other “stuff” >> behind them speaking only OSPF and require a injected default route. >> Router A and B are connected to different internet backbone providers using >> BGP. >> Internally I use iBGP and OSPF. I do not redistribute OSPF routes into BGP, >> nor do I do the opposite. >> Router A injects a default route into the network using OSPF’s >> default-information originate metric 100. >> Router B also injects a default route into the network using OSPF’s >> default-information originate metric 110. >> >> So, right now all my outbound traffic goes out through router A (because of >> the metric 100). Inbound traffic comes through both internet connections, >> based on the preferred BGP route. >> Since the IGP (ospf) has the lower IGP metric (in comparison to ibgp) the >> ospf default routes (0.0.0.0/0) routes determine the flow of outbound >> traffic. Because of that, I can’t seem to “direct” outbound traffic using a >> local route map (local-preference). Ideally I would like to be able to >> direct outbound traffic as specific as I like. >> >> What is the common setup, in terms of BGP and OSPF, on networks that >> resemble ours? >> >> Thanks >> JB >> >> >> >> >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ >> >> >> _______________________________________________ >> cisco-nsp mailing list [email protected] >> https://puck.nether.net/mailman/listinfo/cisco-nsp >> archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
