15 Apr
2015
15 Apr
'15
11:28 a.m.
Hey Mike, Sorry, the specific issue I'm having is around this paragraph: >If the default route is learned from your upstream, then I would have >expected that you need that set to allow it to be re-advertised to your igp >peers - are you saying that it is /not/ the case? That >originate-default=if-installed will re-advertise the default route >regardless? The issue is that say you have three routers, each distributing a default route to each other (each has their own upstream, but you want all routers to have a path to the internet if their upstream goes down). As soon as you set originate-default=if-installed, that peer does not *receive* a default route on that session. say you have rtr01, rtr02, rtr03. rtr01 has IBGP_RTR02, and IBGP_RTR03 rtr02 has IBGP_RTR01, and IBGP_RTR03 rtr03 has IBGP_RTR01 and IBGP_RTR02 if I set both peers on rtr01 to originate-default=if-installed, then rtr02 and rtr03 receive default routes from their upstreams AND rtr01 Then if I go to rtr02 and set originate-default=if-installed on IBGP_RTR01 peer, rtr02 stops receiving a default route from rtr01, and if it's upstream goes down, it now has no default route. I might lab it up in GNS3 tonight and see if cisco gives the same result - I swear it doesn't, but at this point I'm just darned confused, so maybe it does :-p Yeah, i've noticed the CPU pegging issue - that's why I was only taking default + one-hop-in-AS-path from each provider - a full feed takes ~3 mins to fully process a session up or down on a CCR1009, which leaves a lot of downtime. Been crossing my fingers that V7 comes out soon, because I *really* want to use RouterOS ;) (plus four CCR1009's would take up less space than four 7206's, and look a whole lot sexier) Cheers, Damien On 15 April 2015 at 11:18, Mike Everest <mike@duxtel.com> wrote: > Hi Damien, > > I'm not sure that I fully understand the behaviour that you are reporting > :-} > > redistribute-other-bgp is intended to allow the router to advertise to its > peers route prefixes that it has learned from other peers - which instance > is involved instance itself shouldn't matter (don't think so, but haven't > tested it! ;) > > If the default route is learned from your upstream, then I would have > expected that you need that set to allow it to be re-advertised to your igp > peers - are you saying that it is /not/ the case? That > originate-default=if-installed will re-advertise the default route > regardless? > > If you are saying that the learned route is re-advertised with the nexthop > of the upstream router, then you need to force the nexthop to 'self' - look > for 'nexthop-choice=force-self' attribute under bgp peer settings. > > But I get the feeling that I'm missing the important point of your thread - > if so, sorry about that! :-} > > Regarding alternative platforms, I'm with you on that - routerOS is just > too > good to be easily overcome by lower price - but that's my own opinion, of > course, and you'd expect someone who runs the largest Australia/pacific > distributor of a product to have that opinion! :-D > > About RAM size for BGP tables - the answer is 'a lot' ;) I don't have any > routers myself that contain even one full table, so I can't tell you > exactly > what a full table costs in RAM, but I'm sure that there are others on this > list that can tell you ;) > > What I do know is that when it comes to multiple BGP peers with full global > tables, CPU cost is a lot more important than RAM! The problem is that > current routerOS (v6) is still limited to one thread for routing table > update task, so you end up with one CPU core always pegged, and routing > table update lagging. In one case that I am aware of, it caused sufficient > grief that the network operator had no choice than to take out the CCRs and > replace with other routers. Yes, they cost a lot more (A LOT MORE! ;) but > CCR simply couldn't keep up with that demand. > > I don't know for sure what the actual demand was for that particular case, > but again, someone else on the list might be able to offer some real-world > data on that! > > Cheers, Mike. > > > -----Original Message----- > > From: Public [mailto:public-bounces@talk.mikrotik.com.au] On Behalf Of > > Damien Gardner Jnr > > Sent: Tuesday, 14 April 2015 10:32 PM > > To: MikroTik Australia Public List > > Subject: Re: [MT-AU Public] Passing default route through BGP? > > > > Thanks Mike, > > > > If I set it to originate a default, then it does originate it. After > some > playing, if > > I set it to originate-default=if-installed, then it is > > *passing* the default route it has learnt. However once a session is > > originating default, it will not receive default from that same peer. > > > > I just set it up again, rtr01, originating-default if-installed to rtr03, > and rtr03 > > sees the defaults from its upstream and rtr01 (and the static > > route)l: > > > > [admin@rtr03] > /ip route print detail where dst-address=0.0.0.0/0 > > Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r > - > rip, b - > > bgp, o - ospf, m - mme, B - blackhole, U - unreachable, P - prohibit > > 0 ADb dst-address=0.0.0.0/0 gateway=223.25.113.57 > > gateway-status=223.25.113.57 reachable via vlan308 distance=20 > > scope=40 target-scope=10 bgp-as-path="55707" bgp-local-pref=50 > bgp- > > origin=igp bgp-communities=54320:55707 > > received-from=BGP_IPv4_AS55707 > > 1 S dst-address=0.0.0.0/0 gateway=223.25.113.57 > > gateway-status=223.25.113.57 reachable via vlan308 distance=200 > > scope=30 target-scope=10 > > 2 Db dst-address=0.0.0.0/0 gateway=103.235.52.65 > > gateway-status=103.235.52.65 reachable via vlan99 distance=200 > > scope=40 target-scope=30 bgp-as-path="9482,38285,1221" > > bgp-local-pref=50 bgp-origin=igp > > > > bgp- > > communities=9482:14201,9482:19201,9482:65500,38285:4,38285:20,38285:22, > > 38285:1221,54320:9482 > > received-from=IBGP_IPv4_RTR01 > > > > > > Then I set originate-default if-installed on rtr03, and it's now only > seeing the > > default route from its upstream (and the static route): > > > > [admin@rtr03] > /ip route print detail where dst-address=0.0.0.0/0 > > Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r > - > rip, b - > > bgp, o - ospf, m - mme, B - blackhole, U - unreachable, P - prohibit > > 0 ADb dst-address=0.0.0.0/0 gateway=223.25.113.57 > > gateway-status=223.25.113.57 reachable via vlan308 distance=20 > > scope=40 target-scope=10 bgp-as-path="55707" bgp-local-pref=50 > bgp- > > origin=igp bgp-communities=54320:55707 > > received-from=BGP_IPv4_AS55707 > > 1 S dst-address=0.0.0.0/0 gateway=223.25.113.57 > > gateway-status=223.25.113.57 reachable via vlan308 distance=200 > > scope=30 target-scope=10 > > > > > > I don't have redistribute-other-bgp set to yes, as the documentation > seems > > to suggest that it is only learnt to share routes between BGP instances - > and > > I'm only running one instance on each router? I did try turning it on > tonight, > > and it made no difference though.. > > > > The only filter I have is an accept filter on the _in filter for the iBGP > session, > > to only accept 0.0.0.0/0 if the 54320:9482 etc community is set, as I > was > > randomly getting a default route via IBGP which didn't have bgp info on > it > > (bgp-origin being 'incomplete') - I'm assuming that was when the other > peer > > was sending it's static default route as well as it's bgp learnt route? > > > > Although a slightly related question which may render this all not overly > > needed (though would still be nice to have it working) - how much ram do > I > > need to store four full BGP tables (IPv4 + IPv6) per router? I figured > it > would > > mean needing 2gb of ram, since one full feed of both requires 512mb, but > > reading the Mikrotik BGP FAQ, it looks like maybe I could get away with > 1gb > > of ram? Though that's probably still leaving me needing a CCR as each > edge > > router, as I don't think there's anything 'smaller' with that much > > ram? Even getting 512mb seems difficult. (Edgerouter Lite's are > > starting to look like a good cost point ($150 for 512mb and 3 x gig > ports, > and > > they actually will route gigabit), but I *really* like the CLI on > routerOS, the > > REST API is awesome, and WinBox for quick changes is > > fantastic..) > > > > Thanks, > > > > Damien > > > > > > > > On 14 April 2015 at 09:09, Mike Everest <mike@duxtel.com> wrote: > > > > > Hi Damien, > > > > > > Are you sure it's not being filtered out somewhere? RouterOS > > > definitely advertises default route when configured to do so (i.e. > > > default-originate=if-installed) Of course you would also need to > > > redistribute routes learned from other BGP too (i.e. instance has > > > redistribute-other-bgp=yes set), but judging from your comments thus > > > far, I guess you already know that :-} > > > > > > Does default route show up in "rout bgp ad pr"? > > > > > > Cheers! > > > > > > Mike. > > > > > > > -----Original Message----- > > > > From: Public [mailto:public-bounces@talk.mikrotik.com.au] On Behalf > > > > Of Damien Gardner Jnr > > > > Sent: Monday, 13 April 2015 8:55 PM > > > > To: MikroTik Australia Public List > > > > Subject: [MT-AU Public] Passing default route through BGP? > > > > > > > > Hi Guys, > > > > > > > > Our primary upstream has had a couple of small periods of complete > > > > downtime the last couple of nights, which has given me the > > > > opportunity > > > (lol) > > > > to test our failover with our other two upstreams. > > > > > > > > Found an issue in that it looks like RouterOS doesn't pass default > > > > route through BGP? > > > > > > > > I currently have one router setup per upstream, receives a default > > > > route > > > plus > > > > full feed (but we filter to only directly-connected (one AS hop) > > > > prefixes > > > for > > > > each upstream) > > > > > > > > I then run IBGP between all edge routers. And also run OSPF between > > > > the four edge routers, and the core router, to send a default route > > > > to the > > > core. > > > > > > > > My thinking was that OSPF will redistribute a default route on any > > > > edge router with an active default route (i.e. BGP is up and/or > > > > gateway IP is > > > > pingable) Which works ok, IF the upstream gateway goes down. If I > > > remove > > > > the hardcoded default routes, then it works as expected, but leaves > > > > those routers uncontactable. > > > > > > > > I had also been expecting that the default route from each upstream > > > > was being passed on via iBGP to the other routers - to the point > > > > that I had > > > been > > > > setting localpref on each one based on their cost and available > > > bandwidth. > > > > > > > > On checking tonight, it seems that the 0.0.0.0/0 routes are NOT > > > > being propagated via IBGP? > > > > > > > > I can set default-originate=if-installed, which sends a default > > > > route > > > from > > > one > > > > peer to another, but it is not the one being received on eBGP from > > > > the usptream, as the localpref is wrong. And if I set > > > default-originate=if-installed > > > > on the other peer, that peer stops receiving that default route. > > > > > > > > Has anyone tried this? It works fine on quagga and cisco, but > > > > doesn't > > > appear > > > > to be working on mikrotik (which if it's correct, makes me glad I > > > > found > > > it > > > > before I'd forked out on another three hardware routers to go > > > > alongside > > > my > > > > CCR when it arrives back) > > > > > > > > Thanks, > > > > > > > > DG > > > > > > > > > > > > -- > > > > > > > > Damien Gardner Jnr > > > > VK2TDG. Dip EE. GradIEAust > > > > rendrag@rendrag.net - http://www.rendrag.net/ > > > > -- > > > > We rode on the winds of the rising storm, We ran to the sounds of > > > thunder. > > > > We danced among the lightning bolts, and tore the world asunder > > > > _______________________________________________ > > > > Public mailing list > > > > Public@talk.mikrotik.com.au > > > > http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.co > > > > m.au > > > > > > > > > _______________________________________________ > > > Public mailing list > > > Public@talk.mikrotik.com.au > > > http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com. > > > au > > > > > > > > > > > -- > > > > Damien Gardner Jnr > > VK2TDG. Dip EE. GradIEAust > > rendrag@rendrag.net - http://www.rendrag.net/ > > -- > > We rode on the winds of the rising storm, We ran to the sounds of > thunder. > > We danced among the lightning bolts, > > and tore the world asunder > > _______________________________________________ > > Public mailing list > > Public@talk.mikrotik.com.au > > http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com.au > > > _______________________________________________ > Public mailing list > Public@talk.mikrotik.com.au > http://talk.mikrotik.com.au/mailman/listinfo/public_talk.mikrotik.com.au > -- Damien Gardner Jnr VK2TDG. Dip EE. GradIEAust rendrag@rendrag.net - http://www.rendrag.net/ -- We rode on the winds of the rising storm, We ran to the sounds of thunder. We danced among the lightning bolts, and tore the world asunder