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Dynamic routers query HELP!!!

Discussion in 'General Cisco Certifications' started by twobellies, Apr 24, 2007.

  1. twobellies

    twobellies Bit Poster

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    Am I correct in assuming that only dynamic routers use routing tables to pass packets on to remote subnetworks. Any help most appreciated!
     
    Certifications: none yet!
    WIP: A+ N+
  2. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    Well i am no Cisco guy but my understanding is that all routers need a routing tables, so that they know where to route the packets.

    The routing table can be manually configured with static routes.

    Or if the router supports dynamic routing protocols such as RIP, RIPv2 or OSPF then the tables can be automatically updated.
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  3. NetEyeBall

    NetEyeBall Kilobyte Poster

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    All Layer 3 Routers (or layer 3 switches) use a routing table to determine the best path for a packet to be routed.

    That is the job of a router. Which hole to throw the packet down. If it can't match up a best route, it looks at a default route. If no default route is set then it discards the packet.

    The routing table is present even if you don't configure it. Once you configure an interface and you bring it up/up it will show up in the routing table as a connected device. You can set up connected routes, static routes, defualt routes, dynamic routes, or even null routes.

    For dynamic routes to work you will have to configure a dynamic routing protocol.

    Hope this helps. It isn't a very detailed post, but if you want to do some additional reading I can suggest some, or if you want to explore it in depth, I can break out my lab and show you the different states of the routing table (ie. from a blank config, to connected devices, to static routes, to dynamic routes and null routes).

    You might have a possible question on a null route. It is a static route matching a host to route those packets directly to the bit bucket. We use it for offending PCs if they are spamming or impacting the network in some way.
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  4. r.h.lee

    r.h.lee Gigabyte Poster

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    twobellies,

    No, you are not correct in your assumption. You can configure static routes that create entries in the routing table.
     
    Certifications: MCSE, MCP+I, MCP, CCNA, A+
    WIP: CCDA
  5. Headache

    Headache Gigabyte Poster

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    I've never heard of a "Dynamic" router before. I know of cisco routers and non-cisco. I know of modular routers and non-modular. I've heard of "Virtual" routers that can be created via HSRP.

    But a "Dynamic router" ? That's a new one on me.
     
    Certifications: CCNA
    WIP: CCNP
  6. NetEyeBall

    NetEyeBall Kilobyte Poster

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    I just chaulked it up that he was meaning a Router with a dynamic routing protocol configured such as RIP,RIPv2, OSPF, BGP, IS-IS, or EIGRP.

    But I did a quick search and Microsoft uses the terms Static Router and Dynamic Router.

    From the article is seems a Static Router is a router that uses static routes to complete the Routers routing table, where as a Dynamic Router is a router that uses a dynamic routing protocol to build a routing table and then update it when the network topology changes.

    Here is the article

    http://www.microsoft.com/technet/pr...rv/reskit/intwork/inac_uni_hqtf.mspx?mfr=true

    But a Layer 3 Router is a Router, and then you might talk of which routing protocol you have running on the router or how your routes are programmed into the routing table. I don't think I would use the term Dynamic Router or Static Router. But the terms are out there...just like Default Gateway....


    :)
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  7. Headache

    Headache Gigabyte Poster

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    Thanx, NetEyeBall.

    You learn something new everyday. Although the linky doesn't quite say what you call a router that is configured with both a routing protocol and a static route. So I thought for the sake of brevity, let's just call that one a "Dynamo-Static" router and be done with it. :rolleyes:
     
    Certifications: CCNA
    WIP: CCNP
  8. NetEyeBall

    NetEyeBall Kilobyte Poster

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    I like that!
     
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  9. Tinus1959

    Tinus1959 Gigabyte Poster

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    It updates its routing table automaticly, hence it is a dynamic router.
    Your mobile phone still works when you are standing still.
     
    Certifications: See my signature
    WIP: MCSD, MCAD, CCNA, CCNP
  10. Headache

    Headache Gigabyte Poster

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    The question remains though: is a dynamic router still a dynamic router if you also have a static route configured ?
     
    Certifications: CCNA
    WIP: CCNP
  11. NetEyeBall

    NetEyeBall Kilobyte Poster

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    NO! Its a dynamo-static router! Gosh!!!! Get with the program! ;)
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  12. Headache

    Headache Gigabyte Poster

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    [​IMG]
     
    Certifications: CCNA
    WIP: CCNP

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