Transcript RSVP & RSVP-TE

ReSerVation Protocol (RSVP)
Presented by
Sundar P Subramani
UMBC
Overview
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Background
Working of protocol
Messages
Policies
State maintenance
Conclusion
Background
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Best effort routing
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Point-to-point model routing
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insufficient for current applications
Applications demand multipoint-tomultipoint
Solution?
Resource reservation
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Reserve resources along path
Two approaches
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Sender initiated
Receiver initiated
Latter is better
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Heterogeneous requests
Scalable
Stable – except at leaf nodes
Admission control
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Network has finite resources
To maintain specified QoS guarantee
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Admission control
RSVP
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Used to specify QoS by applications
Not a routing protocol
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Internet control protocol
Establish and maintain reservations
Working of RSVP
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Traffic in RSVP defined in terms of
Session
 Filter Spec
 Flow Spec
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Session
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Defined
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Destination IP address
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Unicast/Multicast
Destination port number
Filter Spec
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Several senders in one session
1 sender -> 1 destination  data flow
A data flow specified by filter spec
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Sender IP address
Optional port number
Flow Spec
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Routers informed of traffic parameters
of
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Sender – TSpec (?)
Receivers – RSpec
Above two form the flowspec
RSVP Messages - PATH
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Sent periodically by sender towards all
destinations
Sets up path from sender to each destination
Contains TSpec
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Based on token bucket model
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Maximum bandwidth
Token bucket size
Maximum packet size
RSVP Messages - PATH
RSVP Messages - RESV
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Receivers request for resources using
RESV message
Sent upstream
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Set by PATH messages
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 if no senders no reservation could be made
Merged as message proceeds upstream
RSVP Messages - RESV
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RESV messages propagated upward
only if
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Reservation at that particular router is less
than requested QoS parameters
Helps in conserving resources in a
muticast setting
RSVP Messages - RESV
RSVP Messages - Teardown
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Two types of tear down
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pathtear
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Initiated by sender
resvtear
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Initiated by receiver
Policies
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Two policies determine the reservation
request acceptance
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Admission control
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Does network have enough resources?
Policy control
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Does the element have permissions to make
reservation?
Policies
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If RESV accepted reservation made
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Else error message sent to the receiver
Receiver could also request for
confirmation in RESV message itself
Soft state
 Routers along path would remove
reservations based on timeouts
 PATH and RESV sent periodically
 Keeps the reservation alive
 Advantage
 Network resource not reserved forever in case of
node failure
 Disadvantage
 Message overhead
RSVP TE
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Establish LSP in MPLS networks
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MPLS MultiProtocol Label Switching
LSP Label Switched Path
Essentially enables source routing
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Once path specified incore routers route
packets based on labels
Used in optical networks
Implementation status
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Implemented in
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MAC OS
Windows 2000, XP
BSD
Conclusion
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RSVP helps to conserve network
recourses for multicast traffic
Periodic message transmission
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Increases network traffic
Suggestion
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Implicit signaling mechanism
References
[1] L. Zhang, S. Deering, D. Estrin, S. Shenker, and D. Zappala,
“RSVP: A new resource reservation protocol,” IEEE Network, vol.
7, no. 5, September 1993.
[2] http://www.tml.hut.fi/Opinnot/Tik-110.551/1997/rsvp.html
[3]http://nislab.bu.edu/sc546/sc441Spring2003/rsvp/RSVP.htm
[4] http://www.javvin.com/protocolMPLS.html
[5] http://www.javvin.com/protocolRSVPTE.html