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TOPIC: BW statements on serial sub-intfc

BW statements on serial sub-intfc 14 years 5 months ago #2496

Are bandwidth statements used in any other way than reporting, MIBs, and routing decisions? Will they limit bandwidth consumed by the traffic flow on that sub-interface? If so, Isn't it better to set a BW of a particular sub-interface (DLCI) to be equal to the port speed of the other end as opposed to the pvc cir?

Any thoughts?

Re: BW statements on serial sub-intfc 14 years 5 months ago #2602

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To the best of my knowledge, bandwidth statements do not acutally set the speed or bandwidth on an interface.

They are only used as 'information' for routing protocols that use such a metric to calculate the best routing path.

For example, OSPF routing protocols take in consideration the link's bandwidth, in this case, the bandwidth value is required on each interface to help the routing protocol make it's routing decision. On the other hand, RIP uses hop counts as a metric, so the bandwidth value is simply useless as the routing protocol will make no use of it.

In all material I have read, I've never come across a statement that states the 'bandwidth' command is able to limit the consumed bandwidth.

As far as setting the bandwidth on a sub interface to be equal to the port speed of the other end, I'm really not sure, though I can't see any benefits to it or why someone would want to do that.

I'll have to dig up my cisco books in order to see if I can find further information on it.


Re: BW statements on serial sub-intfc 14 years 5 months ago #2605

Oops, I think on some earlier post I said it was possible ! ;)
Lemme know if you find a cisco command that does limit bandwidth.. most of the time everyone is crying out for more more more.. never had to give em less !

UHS, I wanted to ask you, you have a telecom background don't you ? What exactly were you involved with ? I'm quite keen on getting a little bit of a grounding on some telecommunications technology.. ethernet -> ip -> tcp is really running out of fun things to try out. I'm not happy enough at the bit level.. I'm looking for info signal encoding, voltage specification, POTS info.. anything I might be able to pick your brain for ?

telecom brain picking 14 years 5 months ago #2707


Thanks for the info, I really just want to limit other PVCs from stepping on SNA by say kinking off an FTP or DB synchronization (Notes, PostgresSQL, AD) which would each swell to available B/W on the hub side and kill SNA and some green screen legacy APPs.

As far as telecom background: Bell Telephone(SDN, ISDN, voice/data/PBX, installation/maintenance then switching: 4/5ess, then inside plant: cabling, CO work: DACS/muxes/repeaters testing (T-bird) BIRT testing. Then AT&T all of the above, then FRAME relay/ATM or any HI-Speed PACKET switching including SONET/VoIP/MPLS.

You must remember I've been doing that for 20yrs.....Sooo, pick away!

Re: BW statements on serial sub-intfc 14 years 5 months ago #2711

Wow! 20 years in the industry... hmmm it just occured to me I've only been alive a little longer than that ;). Time for you and tfs to face-off for 'oldest member' (if you provoke him he starts muttering about 'the good old days ... tape drives... ENIAC....')

Any good resources I could start out with ? I'd be most interested in WAN technology, VoIP and the good old telephone system.
If you've got a few bookmarks you could throw my way....

or perhaps we could figure out some way for you to write a little telecom primer for the site if you ever have time. Would you be interested in something like that ? Because we've been keen to start a members submission section and off late we've been scouting the boards for folks with skills who can help contribute in some small way.

It can never be a bad thing to have your name and material published on a site with around half a million hits a month :) Not to mention if you've visited you'll notice that Chris has been 'networking' in more ways than one :) Given that they're ranked in the 6 million hits range at alexa, that can only be a good thing for us.

Cheers mate !

Re: BW statements on serial sub-intfc 14 years 4 months ago #2748

Yeah Sahirh, I've got kids that are close to your age (20 and 18!) 42 y/o here! I'm gonna be really swamped at work (and home for that matter) for the next month or two, I'm migrating a network to a new provider. 39 of 70 or so sites are going on a newly designed frame relay WAN. Guess who the designer/engineer/technician/whipping boy is? All of this and still taking care of the old network. I'm gonna be doing nothing but coffee, cigars, sex, and networking for the next 6 or 7 weeks.

I'll try to stop in here a bunch but I haven't been on lately due to the crunch. I needed to migrate two of the sites in an emergency lost lease situation by the end of Feb. and I'm almost there. I'm pretty new to the low end cisco equipment so I'm really struggling. I'm also mid build of a dual oc3 accu-ring at my Corporate office, so as you can see I'm pretty damn busy.

After that shakes out, I'd be pretty happy to maybe contribute some white papers although I must warn you, I was a journalism major in college and although my tech-writing will be accurate, I like to get a little sarcastic/humorous/cynical so... I may teach but I may offend also. Maybe something along the lines of the "x for dummies" EXTREME series (X-games telecom-freestyle?) LOL

Anyway I popped on here to start a new topic so...keep this dialogue going and look to my other one 'cause I really need some Cisco2620xm and 3745 help and even though has been a great help, I need real human support. I'll call it Frame Relay Help.

When I get a spare moment I'll dig up some basic telecom stuff, has some pretty good stuff as well as Google'ing for answers works wonders.
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