1 / 14

ATM: A view from the trenches

An introduction to my experience with ATM in a Cisco environment at Northwestern University, reviewing basic ATM theory and LANE, and discussing NU's network topology.

sashe
Download Presentation

ATM: A view from the trenches

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ATM: A view from the trenches .

  2. Introduction • Laura Grill: l-grill@nwu.edu • *my* experience with ATM • cisco environment at Northwestern University

  3. Agenda • Why ATM? • Review of basic ATM theory and LANE • A look at NU’s network topology

  4. Why ATM? • 1996 ATM was the next big thing • connection oriented benefits of circuit switched using virtual circuits • efficient use of bandwidth as in packet switched • Decision was made at executive level for: • combine voice and data worlds • ATM to the desktop • 1997 built ATM backbone and bought OC-12 to Ameritech NAP • to handle voice data and video to and from the university

  5. New technologies:New strategy • The enabling technologies that make it feasible to integrate services w/o ATM • voice over IP • QOS for connectionless networks • gigabit ethernet • Today, ATM as a backbone and wan technology w/ no plans to grow it • Moving gigabit into the backbone (keeping existing ATM) • Frame versus cell: I'd rather have frames

  6. Basic ATM theory • Connection oriented vs. connectionless • 53 byte cells • Uses virtual circuits, identified with VPI/VCI

  7. Broadcast based "legacy" protocols • IP, IPX, AppleTalk (use broadcast discovery) • Why is this a problem? • Catch 22 - can’t talk on the network until a circuit is established and can’t establish a circuit without an address • Can’t broadcast on the phone network (no mechanism for this)

  8. Ways to solve the broadcast problem • RFC 1483 [native IP over ATM] • RFC 1577 [classical IP] • LANE (LAN Emulation) • MPOA

  9. LANE system • 3 servers: LECS, LES, BUS • 1 client: LEC

  10. Servers • LECS - LAN Emulation Configuration Server • hold information about the LES for each emulated LAN and gives that info to the LEC when it comes on-line • LES - client register their MAC and ATM address with the LES • BUS- maintains a VC that connects all the clients together emulated a broadcast

  11. Client • LEC - LAN Emulation Client (can be a host or router or switch)

  12. Procedure for a LEC to become part of the emulated LAN • LEC comes up and creates VC to LECS (using well known address or ILMI or statically configured) • LECS tells it what to emulate and who the LES is and what it's ATM address is • The client then registers it's MAC and ATM address with the LES • LES assigns a BUS • At this point many VC’s have been built to mesh all the LEC’s together

  13. ATM Topology at NU • See diagrams • ATM as a backbone technology to connect buildings to the core • use ATM for our WAN - OC-3c to NAP and OC-3c to Chicago campus • Some FDDI still remains • Will add gigabit this year

  14. The end • Questions?

More Related