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Stupid question about serial links...

Discussion in 'General Cisco Certifications' started by Firemouse, Sep 14, 2007.

  1. Firemouse

    Firemouse Bit Poster

    Okay, so I got my CCNA about a month ago. I'm now an expert on configuring everything Ive learned and I know the concepts well, but because I only have experience in the lab and classrom, I have a really stupid question. The topic of serial links werent covered in depth in the course; Im wondering how serial links are used in the real world? I thought they only go up to 128Kbps... This is great for creating a network that just sends routing updates and ping commands, but come on 128Kbps can't be used for anything great. And every cisco lab ive done has used serial links. I havn't gotten into my CCNP courses where this would probably be made clear for me, but im probably just missing somthing really small here. So how are routers interlinked with other routers and WANS in the real world?

    Any insight is appreciated!
    Certifications: CCNA, MCP
  2. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

    Sorry, mate, don't take this the wrong way, but you're not an expert until you're able to do it in the real world with your eyes closed, carrying on a conversation with someone else about something completely different, while users are breathing down your neck.

    And that's why you're not yet an expert, because that's not the case at all. What do you think a T1 uses for connectivity? Serial links default to a bandwidth of 1544 Kbps.

    Actually, all this would be made clear by getting some real-world experience and seeing it for yourself. I know you're in some sort of class... but the CCNP really isn't going to help you much unless you're getting experience (real world, not lab) in this stuff before you pursue it. Just my opinion based on what I've seen in the IT career field...

    How are they interlinked? Ethernet, serial, and fiber, mostly, using a variety of technologies... ISDN, Frame Relay, T1, leased line, fiber link, etc.

    Best of luck to you! :)
    Certifications: CISSP, MCSE+I, MCSE: Security, MCSE: Messaging, MCDST, MCDBA, MCTS, OCP, CCNP, CCDP, CCNA Security, CCNA Voice, CNE, SCSA, Security+, Linux+, Server+, Network+, A+
    WIP: Just about everything!
  3. Spice_Weasel

    Spice_Weasel Kilobyte Poster

    There are a large variety of WAN types in use - Various DSL, T1/E1 (and greater), frame relay, ISDN, MPLS and many others - there is a wan technology for almost any requirement. Most WAN links will either use a specialized interface (eg a DS3 card on a 3840) or you will get an ethernet handoff. For example, a 100 Mbps optical WAN link may go through a transceiver and be presented to the router as fast ethernet. Serial interfaces can be used for quite a few useful WAN technologies such as T1/E1, frame relay and ISDN, and high speed serial interfaces go up to 55 Mbps. Of course, as WAN speeds are continually increasing, older serial interfaces are less and less useful, but still can be handy.

    Spice Weasel
    Certifications: CCNA, CCNP, CCIP, JNCIA-ER, JNCIS-ER,MCP

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