Hardest CCNP topic?

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  • vinbuckvinbuck Member Posts: 785 ■■■■□□□□□□
    mattau wrote: »
    very true. I have absolutely no idea why they are talking about mpls and metro ethernet in the routing protocols sections. I basically just ignored that bit

    The reason they use MPLS in the examples is because most service providers use MPLS in their networks. Many "Metro Ethernet" type services are delivered via MPLS so the book is using it as an example of a type of WAN technology you are likely to see in real world production. It would be no different than the mention of Frame Relay or ATM as your primary WAN option in the Cisco material of 5-10 years ago.

    EoMPLS (I think they call it L2VPN) is one of the most common - it allows you to transport a VLAN across a Layer 3/MPLS network by encapsulating a layer 2 frame inside of an MPLS packet and link two networks via Layer 2.
    Cisco was my first networking love, but my "other" router is a Mikrotik...
  • pertpert Member Posts: 250
    I have no problem understanding the concepts or the act of studyiing. Hardest part is staying committed to studying for 3 tests when there is absolutely no pay off until you've finished them all. Of course you gain understand and further your knowledge, but good luck parleying that into any financial pay off. Some of the other NP tracks are even worse (voice). Of course, it would be even worse if these were all on 1 test, doesn't stop me from complaining about it though.
  • netdogonetdogo Registered Users Posts: 2 ■□□□□□□□□□
    IPV6 (as stated elsewhere) is still difficult for me because I rarely use it. Overall I would say OSPF was the most difficult topic to look into and was almost my downfall when taking 642-902. There's so much to it that I hardly ever come across; LSA states, DR versus BDR, virtual links, all the types of areas, blah. I wish the exam was more in depth on BGP because I have to deal with that everyday, but from what I've read BGP is more a service provider topic anways.
  • vinbuckvinbuck Member Posts: 785 ■■■■□□□□□□
    netdogo wrote: »
    IPV6 (as stated elsewhere) is still difficult for me because I rarely use it. Overall I would say OSPF was the most difficult topic to look into and was almost my downfall when taking 642-902. There's so much to it that I hardly ever come across; LSA states, DR versus BDR, virtual links, all the types of areas, blah. I wish the exam was more in depth on BGP because I have to deal with that everyday, but from what I've read BGP is more a service provider topic anways.

    Depends on your environment and how many routes you need to carry...IGPs will work well up to a few hundred and can hold several thousand max if it's not in constant flux, but BGP was designed to carry several hundred thousand routes that are always changing. Many large enterprises are running iBGP due to its stability when you have a large number of transient routes. That is where BGP really shines and why it is used on a fluid network like the Internet - it can handle large fluctuations in the routing tables and has dampening mechanisms to deal with it.

    The downside is that it doesn't converge nearly as quickly as the IGPs

    I would cringe to see an OSPF network that was constantly adding and deleting hundreds and thousands of routes. Use the IGP where you expect overall stability and use BGP when dealing with stuff that comes and goes.
    Cisco was my first networking love, but my "other" router is a Mikrotik...
  • EildorEildor Member Posts: 444
    vinbuck wrote: »
    Many large enterprises are running iBGP due to its stability when you have a large number of transient routes. That is where BGP really shines and why it is used on a fluid network like the Internet - it can handle large fluctuations in the routing tables and has dampening mechanisms to deal with it.

    I was under the impression that iBGP should never be used as your networks main internal routing protocol -- wouldn't that just result in horrible convergence times?
  • networker050184networker050184 Mod Posts: 11,962 Mod
    Eildor wrote: »
    I was under the impression that iBGP should never be used as your networks main internal routing protocol -- wouldn't that just result in horrible convergence times?

    With iBGP its all about nexthop reachability. If you are using loopbacks as your nexthop that reside in your IGP then you should still have fairly fast convergence.
    An expert is a man who has made all the mistakes which can be made.
  • EildorEildor Member Posts: 444
    With iBGP its all about nexthop reachability. If you are using loopbacks as your nexthop that reside in your IGP then you should still have fairly fast convergence.

    I'm confused. Why would you run iBGP as your main routing protocol when you're going to have to run an IGP on top of it anyway? I mean, I can understand running iBGP on specific routers, but in the entire network? Is that really what is being said here or am I just confused?
  • networker050184networker050184 Mod Posts: 11,962 Mod
    It really depends on the network you are dealing with. If you need full internet routes throughout then yes, run iBGP everywhere. If this is an enterprise network with one router as the exit point you aren't going to have to worry about that. If its a service provider/large enterprise with multiple exit points then you are going to want routes down farther in your network for intelligent routing decisions. If you are providing transit then you are going to want to carry your customer routes also. Lots of things go into the decision basically.
    An expert is a man who has made all the mistakes which can be made.
  • EildorEildor Member Posts: 444
    It really depends on the network you are dealing with. If you need full internet routes throughout then yes, run iBGP everywhere. If this is an enterprise network with one router as the exit point you aren't going to have to worry about that. If its a service provider/large enterprise with multiple exit points at different exit points then you are going to want routes down farther in your network. If you are providing transit then you are going to want to carry your customer routes also. Lots of things go into the decision basically.

    Ah ok, guess it'll make more sense when I actually have some real world experience... or maybe I should consider CCIP after CCNP... although I probably wouldn't be dealing with BGP in any entry level job I guess it's going to be necessary at some point.

    IPv6 is the final topic I need to study before I can start finishing up on ROUTE... and I absolutely hate it. I hated IPv6 at CCNA and I hate it even more now.
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