From: Jens Petter Eikeland (jenseike@start.no)
Date: Thu Feb 23 2006 - 02:45:45 GMT-3
> ok, this is the arguments that I have made also. My consirn is firstmost
> that we have now
> several hundred static routes in the core net, and even I have no overvue
> over all this. We
> are in the process of building the core nett with more core and maybe also
> distribution routers
> (not decided yet)... We are now in the process of readdressing the whole
> net with a new prefix
> that we have got, and mine argument is to use this opirtunity to introduce
> IGP in to the net and make
> a good hiracical design at the same time (it is not today, the addresses
> is all over the place)....
> My other consin is that we are introducing redundancy in to the core, and
> also external, and I am
> trying to convince that this is most eficient and best achived with IGP,
> but other say that this will BGP
> handel better with static routes under. I have to admit that I have not
> worked much in an enviroment
> with the core net is built up with static routes, so I cant really see how
> they would achive this in an
> efficient manner... What arguments can I use here to favor using IGP over
> static... We are running
> BGP on all routes also, but they would ofcourse need something to
> transport the packets. You see
> this guy that is trying to convince my bos that we need to stay with
> static have no experience from
> a dynamic enviroment (oposite of me :-)), so I have a hard time convinsing
> him this.... We dont run
> MPLS, and dont plan that now. We have today two core routers, no
> distriburion layer and access-layer
> routers connect direct to core... We have server park connected to core...
> We are building this core with
> more routers soon and are merging with another company... We will also be
> introducing redundant upplinks
> soon.... I am a cisco guy and have learned cisco way of building a net. In
> mine minde: our nett is a mess, but
> try to tell that to the guy that have designed it :-) not easy... I am
> used to do things the structrual approshe, and
> I am trying to introduce this kind of thinking in to the firm... So, whith
> this sayd if you (and others) could respond
> to what I wrote here that would be great...
>
> Thanks in advance
>
> jens
> ----- Original Message -----
> From: "CCIE KH49279" <ccie_lab@inetiq.com>
> To: "'Jens Petter Eikeland'" <jenseike@start.no>; <ccielab@groupstudy.com>
> Sent: Wednesday, February 22, 2006 5:25 PM
> Subject: RE: bgp/ospf
>
>
>> Jens,
>>
>> Since we do not know what exactly your topology looks like we can still
>> take
>> a nice theoretical discussion about this. Upfront I highly recommend
>> running
>> some kind of dynamic IGP when using BGP.
>>
>> When introducing people to BGP and such I like to explain to them that
>> BGP
>> is reachability protocol which relies on your routing table (built either
>> statically or dynamically) for directions. With this being said, you gain
>> the most from your BGP/IGP combination than you will from BGP/Static. If
>> I
>> rely on static routes for these directions, then I am limiting my scope
>> and
>> capability to provide directions.
>>
>> In the event you pursue selling/using l2/l3 VPN's you will want to use
>> some
>> dynamic IGP to help build these tables as well. I suspect as an ISP you
>> will
>> eventually, if not already, have the requirements to supply BGP and MPLS
>> based VPN's. Go to
>> http://www.netcraftsmen.net/welcher/papers/mplsvpn.html
>> for some info on that.
>>
>> Also consider the use of a dynamic "IGP as the glue that binds all the
>> routers in your AS together". You will find that using an IGP (even rip)
>> can
>> provide a level of scalability that cannot be reached with static routes.
>> (to all the "nay" sayers out there, I am not advocating 100% non-use of
>> static routes, merely limited use).
>>
>> A simple OSPF or EIGRP configuration is more easily managed in an ops
>> environment than hundreds of static routes. If your ops guys need to wrap
>> their heads around each routers static routes, they are then performing
>> the
>> function of the IGP, albeit much less effective and efficient.
>>
>> In a small enough network you can probably configure enough static routes
>> to
>> cover yourself in the event of multiple failures, but most likely you can
>> find scenarios where static routes will give you less than efficient
>> routing, and in some cases big gapping black holes. While using OSPF or
>> EIGRP will allow for "efficient routing" beyond the scope of statically
>> configuring next hops, you will dynamically find the best path which you
>> can
>> tune by the way, so if there are preferences that say an IGP is not
>> selecting, you can tweak to make it happen.
>>
>> I suggest doing some reading of the benefits of ospf and eigrp. Then make
>> your case around how each protocol benefits and impacts both your
>> operations
>> and design. If you deal with a vendor like Cisco or one of their
>> partners,
>> they will be able to provide an array of case study material where an IGP
>> was ultimately selected over static routes, and detail more business case
>> information that you will be able to draw from.
>>
>> Wayne
>>
>> -----Original Message-----
>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>> Jens
>> Petter Eikeland
>> Sent: Wednesday, February 22, 2006 5:11 AM
>> To: ccielab@groupstudy.com
>> Subject: bgp/ospf
>>
>> Can anybody try give me some good arguments for running bgp over ospf
>> internaly compared to running bgp over static routes.. We are going soon
>> to
>> design redundancy in to our net and I am trying to tell that this would
>> work
>> best with running dynamic routing in under BGP. There is a guy that are
>> trying to convince me that running only BGP would be better (with static
>> routes). We have this today. I am trying to say that this is not a good
>> solution. We have over 200 static routes on our core router, and it is
>> not
>> very easy to keep track of anything... Anyway, when we are going over to
>> both have internal redundancy (internally)and external redundancy to our
>> ISP
>> how could this possible be scalable with static routing. We are an ISP,
>> and
>> have got many tousen customers that we are going to get in to to net
>> soon.
>> This will generate more static routes... My suggestion is that we run
>> OSPF
>> internally with BGP on every router in out core net, but he is saying
>> that
>> keeping static routes and BGP is still the best solution..
>>
>> Looking for some good arguments
>>
>> Jens
>>
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