If I advertise a summarized subnet to C and more specific subnets to A and S, would C only failover in event of losing A or S?
On 11/1/2017 10:45 AM, Faisal Imtiaz wrote: > Feel free to call me.. > > 305 921 4141 > > > Faisal Imtiaz > Snappy Internet & Telecom > http://www.snappytelecom.net > > Tel: 305 663 5518 x 232 > > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > > ----- Original Message ----- >> From: "Ethan E. Dee" <e...@globalvision.net> >> To: "Faisal Imtiaz" <fai...@snappytelecom.net> >> Cc: "Mikrotik Users" <mikrotik-users@wispa.org> >> Sent: Wednesday, November 1, 2017 10:31:41 AM >> Subject: Re: [Mikrotik Users] BGP Question >> I'm confused as to why I need iBGP in order to maintain traffic outside >> of my network. Is iBGP able to make changes to my eBGP peering sessions >> that would be helpful to my cause? Or are you just saying I should be >> running iBGP internally to make things less messy in general? >> >> It is possible it is going over my head. Would you be able call me and >> explain? >> >> On 11/1/2017 10:09 AM, Faisal Imtiaz wrote: >>> See answers inline .. >>> >>> Faisal Imtiaz >>> Snappy Internet & Telecom >>> http://www.snappytelecom.net >>> >>> Tel: 305 663 5518 x 232 >>> >>> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>> >>> ----- Original Message ----- >>>> From: "Ethan E. Dee" <e...@globalvision.net> >>>> To: "Faisal Imtiaz" <fai...@snappytelecom.net>, "Mikrotik Users" >>>> <mikrotik-users@wispa.org> >>>> Sent: Wednesday, November 1, 2017 9:51:56 AM >>>> Subject: Re: [Mikrotik Users] BGP Question >>>> I am only referring to traffic leaving the internet and entering my >>>> network. >>> This is called inbound traffic... yes that is exactly what I was talking >>> about >>> too. >>>> I do not want A's traffic to come in thru C unless it is absolutely >>>> dire. i.e. the BGP session on A quits or the router itself dies. >>>> >>> I understand, what you desire to do.. however it may not match up to what >>> your >>> Upstream Desires.. >>> (e.g. if you advertise A's prefix as 'normal' and C's prefix as 'backup'... >>> A's >>> network will see C as local connected and insist on using it over an >>> external >>> route) >>> >>> >>> >>>> I have tried setting BGP prepend to 16x on C. >>> Like I said, that will not work for you... >>> >>>> I have used At&t and Charter Communities to announce a different local >>>> pref (100 on At&t 70 on Charter.) >>>> >>> Sort of right track, but you have to evaluate as to how they have their >>> network >>> configured. >>> Keep in mind Local Pref is only Local to that ASN.. you have to look at >>> their >>> network traffic engineering to determine if you are making yourself more >>> attractive or less attractive ... and use the local pref figures >>> comparative to >>> their's.... i.e. local pref of 70 does not mean the same thing on all >>> networks >>> ! (it is a relative parameter) >>> >>>> No luck. Looking at the looking glass, Charter is largely the preferred >>>> path for HE. See attached. >>> Welcome to solving a 3 dimensional equation... Charter may be Purchasing IP >>> Transit from HE or peering with HE.... >>> Which would explain this.. >>> >>>> Get a similar answer from Cogent's looking glass. >>> Not sure if you are reading the 'details' as some of the LG's show.. or >>> just the >>> 'best path' along with ASN's >>>> I am using OSPF as my IGP btw. I can route the traffic out the correct >>>> router just fine. It is the returning traffic I have a problem with. >>>> >>> This is not the proper way to do things... >>> The recommended best practices are :- >>> >>> use OSPF for distributing loop back IP's >>> use iBGP (a requirement) between all the routers (each router needs one >>> session >>> to each of the others) for re-distributing your BGP routes >>> >>> If you want to run your network as three islands, I suppose you could do it >>> they >>> way you are trying to.. >>> but you are going to have some interesting issues to deal with (especially >>> if >>> there is an anomaly on one of the paths, and your asymmetric traffic will >>> show >>> weird stuff). >>> >>>> Do not be afraid to assume I have no idea what I am doing. I have >>>> followed every rule I can find online so obviously I'm doing something >>>> wrong. >>>> >>>> >>>> >>>> On 11/1/2017 9:45 AM, Faisal Imtiaz wrote: >>>>> I wish there was a simple answer to your question... >>>>> >>>>> But... there are some more questions.... >>>>> >>>>> With the setup you have described..... >>>>> Are you running iBGP sessions between all the routers ? >>>>> if not.. then you are not properly configured. >>>>> >>>>> In today's day and age, one needs to do Traffic Engineering to have the >>>>> type of >>>>> traffic flow one desires. >>>>> I wish there was a 'one solution' that fits all situations.. but >>>>> there isn't >>>>> one. >>>>> Each IP Transit provider is doing their own 'style' of Network >>>>> Traffic >>>>> Engineering >>>>> One has to understand that first and then try to compensate for it. >>>>> One should ask their upstream for a list of their BGP >>>>> Communities, that gives a >>>>> good starting point. >>>>> Using the upstream's Looking glass, if available is also a great >>>>> tool in >>>>> verifying the traffic engineering >>>>> >>>>> simply passing ASN's does not work (most of the time, but varies with >>>>> upstream) >>>>> >>>>> BGP Traffic engineering is more like steering a Boat Rudder than steering >>>>> a >>>>> car... :) >>>>> >>>>> If what is listed above makes sense to you, then you have some starting >>>>> points >>>>> to read up and understand BGP >>>>> If the above does not.. then I suggest you get someone to help you with >>>>> the >>>>> setup. >>>>> >>>>> Regards. >>>>> >>>>> Faisal Imtiaz >>>>> Snappy Internet & Telecom >>>>> http://www.snappytelecom.net >>>>> >>>>> Tel: 305 663 5518 x 232 >>>>> >>>>> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>>>> >>>>> ----- Original Message ----- >>>>>> From: "Ethan E. Dee via Mikrotik-users" <mikrotik-users@wispa.org> >>>>>> To: "Mark Grigsby via Mikrotik-users" <mikrotik-users@wispa.org> >>>>>> Sent: Wednesday, November 1, 2017 9:06:27 AM >>>>>> Subject: [Mikrotik Users] BGP Question >>>>>> I am multihomed. I have a router that peers with charter and advertises >>>>>> a few subnets. (Let's call it C) >>>>>> >>>>>> I have a router that peers with AT&T at a tower (lets call it A) >>>>>> >>>>>> And a router that peers with Spirit at a tower (lets call it S) >>>>>> >>>>>> AT&T seems to have quite a low preference to the world. And I have no >>>>>> idea what I'm doing. Though I feel like I do. >>>>>> >>>>>> Nothing works. >>>>>> >>>>>> All three routers are mikrotik. How do I tell the world to forget about >>>>>> Charters advertisements unless you can no longer see AT&T? >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> This message has been scanned by E.F.A. Project and is believed to be >>>>>> clean. >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Mikrotik-users mailing list >>>>>> Mikrotik-users@wispa.org >>>>>> http://lists.wispa.org/mailman/listinfo/mikrotik-users _______________________________________________ Mikrotik-users mailing list Mikrotik-users@wispa.org http://lists.wispa.org/mailman/listinfo/mikrotik-users
