EQBGP: an efficient interdomain QoS routing protocol

1
EQ-BGP an efficient inter-domain QoS routing
protocol

• Andrzej Beben
• (abeben_at_tele.pw.edu.pl)
• Institute of Telecommunications
• Warsaw University of Technology, Poland

2
Outline

• Introduction
• EQ-BGP protocol
• Performance of EQ-BGP
• Summary

3
Introduction (1)

• Providing end-to-end Quality of Service in IP
  networks still remains a challenging task
• Different types of traffic and QoS objectives
  VoIP, VTC, Multimedia Streaming, high throughput
  data,..
• Different network technologies LAN, WLAN, xDSL,
  UMTS, IP core, etc.
• Recognised approaches
• single domain network DiffServ, IntServ, MPLS
  currently deployed in GENAT, Q-BONE, AQUILA, ...
• multi-domain network
• Concept of end-to-end classes of service (e2e
  CoS) ITU-T, IETF, IST EuQoS (www.euqos.org)
• Path computation architecture (PCE IETF)
• user probing approach
• ...

4
e2e CoSs concept (1)

• The end-to-end Classes of Service
• represents a specific set of traffic requiring
  from network similar QoS guaranties, e.g. VoIP,
  multimedia, guaranteed throughput, ...
• are offered to the users as Globally Well Known
  services
• are mapped into local CoSs offered inside
  particular domains and on inter-domain links

5
e2e CoSs concept (2)

• The QoS level offered by e2e CoSs depends on
• QoS level offered by particular domains and
  inter-domain links
• The routing between source and destination
• However, BGP-4 establishes paths based on AS
  path length that may be not suitable
• Solution to enhance BGP-4 protocol with QoS
  features gt EQ-BGP (Enhanced QoS Border Gateway
  Protocol)

6
EQ-BGP protocol (1)

• Objective
• to fix inter-domain routing paths that for
  particular e2e CoS offer the most attractive QoS
  level, e.g. lowest delay, jitter, losses,...

7
EQ-BGP protocol (2)

• New entities of EQ-BGP
• New QOS_NLRI attribute of update messages, that
  carries information about e2e CoSs and values of
  QoS parameters, e.g. delay, jitter, losses,
  offered on a given AS path
• QoS aware decision algorithm, that allows to
  select paths taking into account QoS objectives
  of e2e CoS
• QoS assembling function, that calculates
  aggregated value of QoS parameters
• Multiple routing tables, as e2e CoSs usually need
  disjointed paths

8
EQ-BGP protocol (3)
9
EQ-BGP protocol (3)
QA-gtB
QC
QB
QB-gtC

• Finally, all routers has information about QoS
  offered inside its domain and on inter-domains
  links. So, they start to exchange these
  information.

10
Performance of EQ-BGP (1)

• Objective
• to analyse the impact of new EQ-BGP entities on
  network convergence
• Methodology
• We compare the performance of EQ-BGP with
  standard BGP-4 protocol based on convergence
  metrics
• Network convergence time time elapsing from the
  occurrence of stressing event till the end of
  processing the last update message
• Number of update messages that need to be
  exchanged
• NS2 is used for simulation experiments

11
Performance of EQ-BGP (2)

• Assumptions
• Basic network stressing events
• Advertisement of a new route
• Withdrawal of the existing one
• Each AS is represented by a single router
• Network topologies
• Full mesh
• Ring
• Representative for the Internet(B.Premore,
  SSFnet)
• Different number of ASs
• A single e2e CoS targeted for assurance mean
  delay
• tree strategies for assigning QoS

12
Performance of EQ-BGP (3)

• Convergence time after advertisement of new
  route
• - randomly chosen AS advertises route
• - 100 simulation runs

• Conclusions
• EQ-BGP gives stable routing
• Full mesh network converges independently from
  the applied protocol
• EQ-BGP protocol needs a bit more time to converge
  in case of ring and Internet topologies

13
Performance of EQ-BGP (4)

• Convergence time after withdrawal of route
• - randomly chosen AS withdraws route
• - 100 simulation runs

• Conclusions
• EQ-BGP gives stable routing
• EQ-BGP protocol converges faster then standard
  BGP-4

14
Summary

• The approach for providing e2e QoS in
  multi-domain network based on e2e CoSs was
  investigated
• The Enhanced QoS BGP protocol (EQ-BGP) was
  proposed for supporting e2e CoS concept
• Obtained preliminary simulation results confirm
  that
• EQ-BGP gives stable routing
• Network convergence is similar to BGP-4
• Further work
• Evaluation of other stressing events, like link
  or node failure, route flapping
• Evaluation of scalability in large networks
• Evaluation in test-bed