Determine bw for VLAN

larkspurlarkspur Posts: 235Member
I am using a NetFlow collector. I have set up IP groups to determine how much bandwidth vlan 2 is using.

My question is to accurately determine how much bw a vlan is using do I need to total up the speed that each interface particapting in that vlan is set to?

example:
3 100 meg interfaces in vlan 2 = 300000000 bps

vlan 2 bandwidth capaicty is 300000000 bps.

Would this be correct?
just trying to keep it all in perspective!

Comments

  • rossonieri#1rossonieri#1 Posts: 800Member
    hi larkspur,

    if you are talking about theoritically full rate data transfer - then yes its about 3x100Meg in VLAN2.
    but we use a multiplexing/compression ratio - not all your 3 interfaces talk in the sametime - using the same protocol (different protocol utilize different speed etc), cabling distance, electricity and so on.

    cheers.
    the More I know, that is more and More I dont know.
  • Paul BozPaul Boz Posts: 2,621Member ■■■■■■■■□□
    It depends more on the bandwidth of your trunk links than anything else. If you have 3 100mb vlan ports that are trunked with a 100mb port and have to send packets across that trunk link your capacity drops down to 100mb. You can't shove 10 pounds of sausage into a 3 pound casing, after all.
    CCNP | CCIP | CCDP | CCNA, CCDA
    CCNA Security | GSEC |GCFW | GCIH | GCIA
    [email protected]
    http://twitter.com/paul_bosworth
    Blog: http://www.infosiege.net/
  • larkspurlarkspur Posts: 235Member
    this is my bad for not providing better info.

    core swicth (6509)

    trunk links to access\distribution swicthes (3750g's)

    trunk link speed is 1 gig.

    So there are 3 1 gig trunk links to the 3750's which particpate in vlan 2.

    so the total bandwidth for vlan 2 would be 3 gig or 3000000000 bps and not the combined port speed of all interfaces ( server etc..) particapting in vlan2 ?
    just trying to keep it all in perspective!
  • rossonieri#1rossonieri#1 Posts: 800Member
    larkspur wrote:
    this is my bad for not providing better info.

    core swicth (6509)

    trunk links to access\distribution swicthes (3750g's)

    trunk link speed is 1 gig.

    So there are 3 1 gig trunk links to the 3750's which particpate in vlan 2.

    so the total bandwidth for vlan 2 would be 3 gig or 3000000000 bps and not the combined port speed of all interfaces ( server etc..) particapting in vlan2 ?

    yes - i wished i know about trunk lines more better.

    the global def about trunk line is a line (either single nor aggregrate) which carries multiple line.
    the main line - is that the carried line BW will never exceed the trunks.

    does a cat6500 single 1 gig port will carry a cat2900 24x100meg on their trunk?
    the answer is very clear.
    cheers.

    HTH.
    the More I know, that is more and More I dont know.
Sign In or Register to comment.