M. Peyravian et R. Onvural, ALGORITHM FOR EFFICIENT GENERATION OF LINK-STATE UPDATES IN ATM NETWORKS, Computer networks and ISDN systems, 29(2), 1997, pp. 237-247
Citations number
7
Categorie Soggetti
Computer Sciences","System Science",Telecommunications,"Engineering, Eletrical & Electronic","Computer Science Information Systems
In the routing framework defined by the ATM Forum Private Network Node
Interface (P-NNI) working group, each node broadcasts link-state upda
te (LSU) messages (which include information such as available bandwid
th, maximum delay, etc.) about the outgoing links attached to it to ot
her nodes in the network. For each connection request, the source node
selects an end-to-end route that meets the quality of service (QoS) r
equirements of the connection based on the most recent information tha
t it has about network links. Up-to-date information about network lin
ks is, therefore, key to making ''good'' routing decisions. The trigge
ring of LSU broadcasts after adding or removing a single connection on
any link would certainly enable optimal paths to be calculated but at
a potentially significant cost in processing and bandwidth. A periodi
c update scheme, on the other hand, might be more preferable since it
can be used to bound the frequency of updates at the expense of delayi
ng important updates (such as those reporting large changes in link lo
ad), The goal of an efficient LSU generating algorithm is, therefore,
to provide ''accurate'' information on link loads while keeping the nu
mber of LSUs under control. In this paper, we investigate the issue of
when to broadcast LSUs and its effects to the network performance, A
simulation model is built to model the basic routing framework develop
ed at the ATM Forum P-NNI working group, Based on the intuition gained
by running the simulation model with different schemes and parameters
, a hybrid LSU generating algorithm, combining event-driven and period
ic update strategies, is proposed to substantially reduce the number o
f LSUs generated in the network without a significant negative impact
on the network performance. The proposed algorithm is not limited to t
he P-NNI framework and it can be used in networking technologies that
are based on the link-state principles.