BGP which OSI layer?

sydneysundarsydneysundar Member Posts: 19 ■□□□□□□□□□
All,

I am attempting CISSP questions from SH .. BGP is marked as a routing protocol in network.. while BGP (border gateway protocol) is at application layer by many other sources(coutesy google)..

as gateway are operating at Application layer, this is confusing..

please explain.

regards
sundaricon_rolleyes.gif

Comments

  • warriorfan808warriorfan808 Member Posts: 27 ■□□□□□□□□□
    I'll take a shot at it. BGP is treated a little different because it runs on TCP port 179, which is an application port. Just like other applications, it's defined in the Application layer. I know it's a bit odd because it's a routing protocol and when people think routing, they think the Network Layer.
  • TheFORCETheFORCE Senior Member Member Posts: 2,298 ■■■■■■■■□□
    All,

    I am attempting CISSP questions from SH .. BGP is marked as a routing protocol in network.. while BGP (border gateway protocol) is at application layer by many other sources(coutesy google)..

    as gateway are operating at Application layer, this is confusing..

    please explain.

    regards
    sundaricon_rolleyes.gif

    You are getting confused by the word "network" BGP is used to exchange routing information between AS's, the book doesnt say that BGP is operating at the network layer rather it helps route information between networks.
  • sydneysundarsydneysundar Member Posts: 19 ■□□□□□□□□□
    Many thanks..

    this came in the practise questions that came along in the CD-ROM.
  • Hunter85Hunter85 Member Posts: 60 ■■■□□□□□□□
    well google says it works in network layer
  • ScottFiestaScottFiesta Member Posts: 19 ■□□□□□□□□□
    Here's a great reference chart in PDF that shows all the protocols mapped to the OSI model plus full acronym lists and other helpful info (PRINT AND LAMINATE FOR REFERENCE). I've read both RFCs (090400 & 1771) and neither are very helpful in clarifying things. Wikipedia lists BGP as Layer 7 but EGP, OSPF, EIGRP etc as Layer 3.

    I don't understand how EGP can be in Layer 3 but BGP can be in 7. I would, however, hazard a guess that my delving too much deeper into this wouldn't be a prudent expenditure of my study time.
  • ScottFiestaScottFiesta Member Posts: 19 ■□□□□□□□□□
    Here's a great reference chart in PDF that shows all the protocols mapped to the OSI model plus full acronym lists and other helpful info (PRINT AND LAMINATE FOR REFERENCE). I've read both RFCs (090400 & 1771) and neither are very helpful in clarifying things. Wikipedia lists BGP as Layer 7 but EGP, OSPF, EIGRP etc as Layer 3.

    I don't understand how EGP can be in Layer 3 but BGP can be in 7. I would, however, hazard a guess that my delving too much deeper into this wouldn't be a prudent expenditure of my study time.
    https://web.archive.org/web/20120529200700/http://www.wildpackets.com/elements/misc/WP_encapsulation_chart.pdf
    and there is the link to the chart icon_rolleyes.gif
  • GessGess CISSP, Server+, SCCM 2012, Project+; J.D. Member Posts: 144 ■■□□□□□□□□
    I made my own OSI Model matrix and had BGP at Layer 3 (Networking) with the routing protocols.
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