Hello everyone
In the context of a single service provider network running MPLS, if a
number of bandwidth constrained LSPs are passing through a particular node
and the sum of the bandwidth constraints for the LSPs is X Mb/s, then is X
the upper bound on the traffic through that node, or is it sometimes
exceeded as well?
Thanks and best regards
Well, yes (if you don't count the additional traffic of signalling/routing
protocols, label imposition, etc) but consider the fact that topologies
change and routing will tend to change the total traffic handled through a
node. LSPs are not static unless you use TE tunnels. Remember that labels
are Forwarding Equivalency Classes and that translates into subnets (whether
they're subnets in a L3 vpn or part of the P network) and the routing is
still handled through an IGP or BGP.
HTH
--WJM IV
William
Thanks for the reply. You say that LSPs are not static unless you use TE
tunnels. Are you referring to the staticness in terms of the path or in the
amount of bandwidth reserved on each link along a fixed path determined at
the time of signalling? Isn't a bandwidth constrained LSP always a TE
tunnel?
Thanks and best regards
Furthermore, I was also wondering, if the bandwidth constraints are upper
bounds, what does the traffic distribution typically look like at an LSR?
We're interested in traffic within a single service provider, non-Internet
traffic. Perhaps most service providers set aside some (dynamic?) pool for
Internet traffic, while making commitments to customer's inter-site traffic.
Thanks and best regards
Anyone?
Anyone?
Furthermore, I was also wondering, if the bandwidth constraints are upper
bounds, what does the traffic distribution typically look like at an LSR?
It clearly depends on what that traffic is.
The MPLS services I am most familiar with carry video traffic, with traffic patterns that look very different from the typical web site (generally the traffic is either on or off, there is very little "burstiness," there can be long periods of basically full usage of the available bandwidth and, if you commit to X Mbps, you had better actually have it, not X - epsilon). I would guess that this is one end of the spectrum, that bursty web traffic is the other, and that most other uses (such as VOIP) fall somewhere in between.
Regards
Marshall
We're interested in traffic within a single service provider, non-Internet
traffic. Perhaps most service providers set aside some (dynamic?) pool for
Internet traffic, while making commitments to customer's inter-site traffic.
Thanks and best regards
William
Thanks for the reply. You say that LSPs are not static unless you use TE
tunnels. Are you referring to the staticness in terms of the path or in the
amount of bandwidth reserved on each link along a fixed path determined at
the time of signalling? Isn't a bandwidth constrained LSP always a TE
tunnel?
Thanks and best regardsWell, yes (if you don't count the additional traffic of
signalling/routing protocols, label imposition, etc) but consider the fact
that topologies change and routing will tend to change the total traffic
handled through a node. LSPs are not static unless you use TE tunnels.
Remember that labels are Forwarding Equivalency Classes and that translates
into subnets (whether they're subnets in a L3 vpn or part of the P network)
and the routing is still handled through an IGP or BGP.HTH
--WJM IV
Hello everyone
In the context of a single service provider network running MPLS, if a
number of bandwidth constrained LSPs are passing through a particular
node
and the sum of the bandwidth constraints for the LSPs is X Mb/s, then is
X
the upper bound on the traffic through that node, or is it sometimes
exceeded as well?
Thanks and best regards--
Muhammad Saqib Ilyas
PhD Student, Computer Science and Engineering
Lahore University of Management Sciences--
Muhammad Saqib Ilyas
PhD Student, Computer Science and Engineering
Lahore University of Management Sciences--
Muhammad Saqib Ilyas
PhD Student, Computer Science and Engineering
Lahore University of Management Sciences
Regards
Marshall Eubanks
CEO / AmericaFree.TV
How about when William says "LSPs are not static." Does he mean "not static"
as in path may change, or that the bandwidth reserved for the LSP may
change? And thanks Marshall for the reply.
Hi,
Hello everyone
In the context of a single service provider network running MPLS, if a
number of bandwidth constrained LSPs are passing through a particular node
and the sum of the bandwidth constraints for the LSPs is X Mb/s, then is X
the upper bound on the traffic through that node, or is it sometimes
exceeded as well?
From my experience with RSVP-TE and LSP tunnels the bandwidth you pin
down for a tunnel is only reserved, not guaranteed. There is nothing
stopping you from creating a 10Mb/s LSP and sending 20Mb/s down
through it. By default only the ingress LSR can do the
policing/shaping. If you don't to that at the head than the rest of
the network will just happily pass the traffic defaulting to its
normal queue handling.
So to answer to your question is - yes you might see more traffic then
you've reserved.
kind regards
Pshem