MRSVP: A Resource Reservation Protocol for an Integrated Services Network with Mobile Hosts

1. MRSVP: A Resource Reservation Protocol for an Integrated Services Network with Mobile Hosts Anup K.Talukdar B.R.Badrinath Arup Acharya

2. Need for QOS • With increase in real-time traffic across the global internet greater and greater demand is being placed on the network. • Factors like packet delay,packet loss rate, jitter significantly affect multimedia and voice traffic. • The traditional Best effort Service of the internet is not good enough for these. • There are basic two models proposed for QOS implementation : • Intserv : Network resources are reserved according to the application’s QOS request and subject to BW management policy • Diffserv: Network traffic is classified and the network resources are allocated preferentially according to the classification.

3. Mobility’s effect on QOS • With the motion of the mobile node the data flow path changes …….. • Packet delay changes • Congestion levels in the new network is different • A overloaded cell may result in lower bandwidth in the new cell • Temporary disruption during hand-offs

4. Work in this space • Loss Profile Application can specify the kind and rate of degradation in data that they can tolerate. use of a hierarchical architecture with a supervisory Host over a set of MSS which is aware of the application’s loss profile and a Loss Profile Transport Sub-layer. • Prediction of motion of the mobile host and multicasting packets to the surrounding cells.

5. RSVP • Is used to reserve resources for both unicast and multicast flows. • Makes simplex reservations and maintains soft-state • Is receiver oriented • Two types of messages: Path and Resv • Each RSVP message carries a Session which contains the destination IP address, the Protocol Id and dest port number.

6. RSVP contd • A Path message contains • the Sender_Template which identifies the particular sender’s packets • Sender TSPEC which identifies the traffic characteristics. • Path messages install the “path state” in the nodes on the way • A Resv message contains • A FlowSpec object : a RSPEC that defines the desired QOS and a TSPEC which defines the traffic characteristics • A filter Spec: set of senders whom the Resv message is to be forwarded to.

7. Reservation Model in MRSVP • Mobile host can make advance resource reservation. • Mobile nodes knows its MSPEC. • MSPEC – The set of locations it would visit during the lifetime of connection. • MSPEC either from the network or local mobile profile. • MSPEC can change dynamically when flow is open. • ACTIVE and PASSIVE reservation. • BW of passive reservations can be used by other flows with lower QOS guarantees.

8. Limitations of RSVP • No passive reservation. • No advance reservation possible from a future location. • Sender IP address and port number identifies the sender in the filter specification. • If path messages originate from several locations in MSPEC, a receiver cannot determine the identity of the mobile host from sender template.

9. Overview of MRSVP • Proxy agents make reservations. Local proxy agent -> Active Reservation. Remote proxy agent -> Passive Reservation. • Two types of path messages. Active path message ->SENDER_TSPEC. Passive path message ->SENDER_TSPEC • Two types of Reservation messages. Active Resv -> Active FLOWSPEC and a passive FLOWSPEC if these are merged. Passive Resv -> Passive FLOWSPEC. • Additional messages. Join Group, Receiver Spec ,Sender Spec, Receiver Mspec, Sender Mspec, Forward Mspec, Terminate.

10. Operation • Sender Host sends active Path messages • Proxy agents send out Passive Path messages • Mobile receiver and its proxy agents receive Path messages once the reservation are setup. • Mobile host sends out a Resv message for active reservation • A proxy for the mobile receiver on receiving a Path message makes a passive reservation on a downstream link and sends a Resv for passive reservation.

11. Protocol Description • Proxy Discovery Protocol • Proxy agent is a MRSVP capable router • Default gateway • Capable of making passive reservation • Capable of notifying the results to the host • PDP uses foreign agent care-of-address from Mobile IP • Two messages • Remote Agent solicitation • Remote Agent Advertisement • Home subnet-HA as proxy Foreign subnet - foreign agent care-of-address as proxy address

12. Reservation of routes • Mobile sender • Sender-anchor node –P the local proxy agent during flow initiation. Flow F split into: • A unicast flow from mobile sender and its remote proxy agents to P • A unicast or multicast flow from P to destination • Mobile Receiver –Multicast flow • Mobile host sends Join-group with multicast address of the group DST and the R_SPEC • Remote proxy agent joins the group • Paths of both active and passive reservation setup.

13. Reservation of routes (contd) Mobile Receiver Unicast flow • Using Unicast routing • Designate a receiver -anchor node • Passive reservation between this node and remote proxy agent ,active reservation between it and the host • Can use the mobile sender as the receiver anchor node too. • Using Multicast routing • using a multicast routing using the multicast address allocated to a mobile host

14. Reservation Routes Join_group C5 C6 Active Path MH2 Active Resv Passive Resv N9 Passive Path N8 N1 N3 N2 N7 N5 N6 N4 C4 C1 C2 C3 MH1

15. Reservation Setup • On receiving the DST address the mobile sender M establishes the split connection: • It sends Sender-Spec and Sender-Spec to the sender anchor node -P • Sender-anchor node checks if already flow has been setup . If so returns that dest port no. else allocates new one p. • Sender-Anchor node sends a message containing the unicast address (P,p) and the sender TSPEC and ADSPEC to to M and its proxies • Next it creates a psuedo-header for M identified by (P,m) with destination address DST.

16. Other issues Merging Active and Passive reservations • Active and Passive reservation are merged e.g. at a sender-anchor node SENDER_TSPEC from mobile sender and its remote proxies are merged to create a single TSPEC to be forwarded • Switching between Active and Passive Reservation • Soft state : Proxy agents have an expiry time with the sender/receiver spec that they receive

17. Design II • Changes the Path messages to include a RSVP object called the MOBILE_ID • MOBILE_ID-Home IP address and RSVP source port of the mobile sender • Source and Sender –Template IP address of the Path message contains this IP address • On receiving this message a Path state with this Mobile_ID object is recorded • In RESV messages this object is used to identify the previous hop

18. Conclusion /Comments • This is the first complete signaling(I believe) mechanism to be proposed for implementing QOS in mobile environments • The scalability and security issues in MRSVP to be investigated • Questions of Scalability are really important as the amount of state to be stored per connection in each router is large.