Source specific multicast routing and QoS issues

1
Source specific multicast routing and QoS issues
Laurentiu Barza
2
Outline

• one-to-many multicast model
• as defined in Source Specific Multicast
• QoS routing issues
• some QoS routing protocols

3
Source Specific multicast model
A datagram sent with source IP address S and
destination IP address G in the SSM range is
delivered to each host socket that has
specifically requested delivery of datagrams sent
by S to G, and only to those sockets. IP
addresses in the 232.0.0.0 to 232.255.255.255
range are designated as source specific multicast
destination addresses and are reserved for use by
source specific applications and protocols.
4
Source Specific multicast terminology
Service model Internet Standard Source-Specific
Network Abstraction group
channel Identifier G S , G Receiver
Operations join, leave subscribe,
unsubscribe
5
PIM - SS

• sparse mode protocol
• only builds source specific shortest path trees
• uses a subset of standard PIM-SM messages
  Hello, Join/Prune
• used for group ranges designated for SSM
• session advertisement tools must advertise a SSM
  address
• used in a space where is deployed IGMPv3

6
Source Specific multicast drafts
Source-Specific Multicast for IP -
draft-holbrook-ssm-00.txt H. Holbrook, Cisco
Systems B. Cain, Nortel Networks PIM-SM rules
for Support of Single Source Multicast Hal
Sandick, Brad Cain - Nortel Networks Source
Specific Protocol Independent Multicast N.
Bhaskar, I. Kouvelas - Cisco Systems Deployment
of PIM-SO at Sprint S. Bhattacharyya, C. Diot,
Sprint ATL L. Giuliano SprintLink
7
Issues in designing a QoS routing algorithm (1)

• the type of distribution tree used ?
• static or dynamic computation of multicast
  distribution tree ?
• centralized or distributed architecture ?
• which states to held in the routers ? soft
  states or hard states?

8
Issues in designing a QoS routing algorithm (2)

• which QoS parameters are used to define the
  constraints ?
• how many QoS parameters used to calculate the
  distribution tree ?
• consider a QoS unicast routing protocol (QOSPF)
  or start from RIP or OSPF and choose the
  appropriate QoS routing path in the multicast
  protocol ?
• tradeoff between too much precomputation and
  signaling

9
Issues in designing a QoS routing algorithm (3)

• tradeoff of the dynamic of multicast routing
  tree (route changing)
• too often instabillity, loss of packets,
  joining latency
• seldom suboptimal routing(network use), path
  too long
• replicated adaptive streams or layered video
  streams ?
• bandwidth reservation or periodical checks of
  the routes ?
• interdomain ?

10
Multicast QoS routing algorithms

• Kompella
• Carlberg Crowcroft
• QoSMIC
• RIMQoS
• QMRP

11
Kompella s algorithm

• first, create a complete graph between the
  source and receivers
• based on Prims minimum spanning tree algorithm
• tree grows from the source
• choose a link that minimizes a given selection
  function
• assume link state info available

12
Carlberg Crowcroft ( spanning-join algorithm )

• a new member broadcast join-request messages in
  its neighbourhood to find on-tree nodes
• the on tree node reply to the new member
• the new member selects the best candidate path
• signifiant communication overhead

13
QoSMIC Quality of Service sensitive
Multicast Internet protoCol

• two search procedures local search and tree
  search
• local search a spanning-join procedure for a
  small neighborhood
• tree search a Manager node sends BID-ORDER
  messages in the tree to select a subset of
  on-tree nodes. The selected nodes send BID
  messages to the new member
• the new member chooses an appropriate path among
  the two sets of candidate paths

14
RIMQoS Receiver Initiated Multicasting with
Multiple QoS Constraints

• assumes a preexisting unicast QoS routing
  protocol that precomputes QoS paths
• a receiver router knows all the state info
  within its domain so it calculates an optimal
  route to the source according to a cost function
• the joining router sends a Request message with
  the complete source route specified in it

15
QMRP A QoS-aware Multicast Routing
Protocol

• the new member initiate the routing process by
  sending a Request message to the core. Request
  message carries the QoS requirements and it
  checks the resource availability at every
  intermediate node
• two searching modes are defined single path
  mode and multiple path mode
• if an intermediate node does not have resources
  it triggers the multiple path mode by sending a
  NACK message back to the previous node. This node
  sends the Request message toward other directions
  than the one defined by the unicast routing path.

16
Work plan

• Select multicast routing and Qos support
  architecture for layered video applications.
  Evaluate.
• Implement the architecture with a video
  streaming application

17
References
QoSMIC http//www.acm.org/sigcomm/sigcomm98/tp/
abs_12.html INFOCOM 2000 RIMQoS
http//www.ieee-infocom.org/2000/papers/722.pdf
QMRP http//www.ieee-infocom.org/2000/papers/413.
ps
18
(No Transcript)
19
S
20
S
21
S
C
M
C
C
22
(No Transcript)