RSVP Path and Res messages

Path message: Resv message A Path message travels from the sender and reaches all receivers in the multicast path. On the way, a Path message stores the necessary information for the receivers. Resv message Reserves the resources by requesting and specifing how much each receiver needs from the resources. The Resv message travels toward the sender (upstream) and makes a resource reservation. If there is only one sender we merge the bandwidth requests into one taking the largest request Different receivers and one sender One reservation for one sender

Merge When there is more than one flow (different senders), the router needs to use reservation styles to accommodate all of them.

Reservation Styles: 3 styles 1. Wildcard/No filter Creates a single reservation shared by flows from all upstream senders 2. Fixed filter – Creates distinct reservations for every data packets from a particular sender, not sharing them with other sender’ packets for the same session. 3. Dynamic filter / Shared-Explicit Creates a single reservation shared by selected upstream senders.

In Figure below a router has two incoming interfaces, A and B, and two outgoing interfaces, C and D. The many-to-many multicast session has three senders -- S1, S2 and S3 -- and three receivers -- R1, R2 and R3. The figure also shows that interface D is connected to a LAN. If the router receives the following reservation request, what will be the reservation value that will be sent upstream (to the source) If the router runs:wildcard-filter reservation 1 ? 4 b ? 3 b Answer: Like merge: single res with the maximum for both 4 4 b 4 3 b

2 3 What about Fixed filter reservation? Answer: S1(4b) s1(4b), S2(5b) Different resv for every sender Answer: Each sender has its flow with the highest request for it. (no sharing) 3 What aboutshared-explicit reservation? Answer: ? (S1, S2) (1b) ? (S1, S3) (3b) (S2)(2b) S1(3b) (S1, S2) (1b) (S2,S3)(3b) (S1, S3) (3b) (S2)(2b) S3 Shares with S2 Answer: the flow is shared between senders in the same path (upstream).