Technically yes...
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 2:44:43 PM > Subject: Re: [Mikrotik Users] BGP Question > 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
