From: Scott Morris (swm@emanon.com)
Date: Wed Aug 11 2004 - 09:03:59 GMT-3
I think the confusion comes with some of Cisco's descriptions. See
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuratio
n_guide_chapter09186a00800b75d2.html
The basic description is that LFI is responsible to sequence and reassemble
packets properly when balancing over multiple links (implying, of course,
that more than one link is necessary).
If you look a little further down though, you do see the
exception/restriction which falls into the specific category you are talking
about! "Interleaving on MLP allows large packets to be multilink
encapsulated and fragmented into a small enough size to satisfy the delay
requirements of real-time traffic; small real-time packets are not
multilink encapsulated and are sent between fragments of the large packets."
Interestingly enough, none of the examples shown make any requirement for
minimum links, which carries the logic that interleaving and fragmentation
will work just as well with only one particular link coming up, because when
'ppp multilink' is used, you can still have a a bundle of one.
Another good document to view (also containing the table of fragmentation
recommendations that I used to have and 'lost'!!!) is
http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080
094660.shtml which shows this using a multilink interface although it is
only applied to a single interface (hence bundle of 1).
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIP, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Wednesday, August 11, 2004 7:20 AM
To: Carlos G Mendioroz; Group Study
Subject: Re: IEWB Lab1 4.7 ppp multilink
Carlos,
I have to disagree with you on this.
If only one bri is used, how can multilink fragment and interleave over
multple paths?
For fragmentation to take place, there needs to be at least 2 paths over
which traffic is sent.
I think where you're getting confused is with the command, ppp multilink.
True, this command is required before ppp will fragment packets, but by
itself, it's not sufficient. There also has to be multiple paths over which
to send traffic.
That's where the 2nd command comes into play. By adding the command, ppp
multilink links min 2, you're insuring that there will always be 2 bri's.
Now, the ppp multilink command can actually fragment packets and split the
fragments across the 2 bri's.
HTH, Tim
----- Original Message -----
From: "Carlos G Mendioroz" <tron@huapi.ba.ar>
To: "Group Study" <ccielab@groupstudy.com>
Sent: Wednesday, August 11, 2004 5:37 AM
Subject: IEWB Lab1 4.7 ppp multilink
> Requirement is to have LFI (Link Fragmentation and interleaving)
> no matter what load on the first channel.
> Proposed answer is to have multilink with minimum 2.
>
> From where should I get the info that I have to dial with two channels
> ? LFI is up as soon as I do multilink AFAIK, so 4.7 does not imply load
> threshold... so for me ppp multilink would be enough.
>
> This is where one gets very picky as to doing the thing they want you to
> do and not what they ask you to do...
> Or am I missing something ?
>
> --
> Carlos G Mendioroz <tron@huapi.ba.ar> LW7 EQI Argentina
>
> _______________________________________________________________________
> Please help support GroupStudy by purchasing your study materials from:
> http://shop.groupstudy.com
>
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Fri Sep 03 2004 - 07:02:41 GMT-3