MPLS additions to RSVP Tunnel identification Tunnel parameter negotiation Routing policy distribution Routing debugging information Scalability improvements LSP merging

Tunnel identification New Session C-Type,, Semantics are that the complete filter specification is the Label Extended Tunnel ID can be used to scope session to a single source router (i.e. ensure globally unique tunnel identification)

Tunnel identification (2) New Sender_Template LSP_ID allows a source to ‘share’ a session with itself. Useful for reroute and bandwidth change operations

Tunnel parameter negotiation LABEL_REQUEST object –Carries L3 protocol ID to describe contents of the tunnel –Range of acceptable label values LABEL object –Carries selected label value Session Attribute/Policy Object –Setup & hold priorities –Flags

Routing policy distribution EXPLICIT_ROUTE_OBJECT –List of IP addresses for loose or strict source route –Carries path for session

Routing debugging information RECORD_ROUTE_OBJECT –List of systems in the path –Useful for loop detection & avoidance debugging policy configuration Subsequently pinning a route

TE Setup Path : ERO (R1->R2->R6->R7->R4->R9) Tunnel ID 5, LSP_ID 1 Resv: Communicates labels and Establishes label Operations Reserves bandwidth on each link Pop R8 R2 R6 R3 R4 R7 R1 R5 R _10F8_c1 UUnet

TE Rerouting - Alternate Path Setup: Path (R1->R2->R3->R4->R9) Tunnel ID 5, LSP_ID 2 Until R9 gets new Path Message, current Resv is refreshed Pop R8 R2 R6 R3 R4 R7 R1 R5 R _10F8_c1 UUnet

TE - Switching Paths Pop R8 R2 R6 R3 R4 R7 R1 R5 R _10F8_c1 UUnet Resv: Allocates labels for both paths Reserves bandwidth once per link PathTear Can then be sent to remove old path (and release resources) 89 26

RSVP scaling issues Refresh packets scale linearly with the number of sessions Sending lots of little packets has high overhead Sessions need not be refreshed independently Still need capacity to deal with peak signaling events (e.g., link failure)

Possible approaches Aggregate refresh messages verbatim –Decreases packet processing overhead –Provides substantial improvement –Trivial modification –Requires a capability bit

Possible approaches (2) Transmit a refresh digest (IS-IS model) –Decreases packet processing overhead –Decreases signaling bandwidth –Increased protocol complexity –Need a capability bit

Possible approaches (3) Run RSVP on top of TCP (BGP model) –Significant departure from ‘soft state’ model –Add router-to-router ‘keepalives’ to provide liveness –Reliability provided hop-by-hop –No refreshes necessary –Must explicitly tear down sessions

LSP merging Merging: multi-point to point LSPs Work in progress Automatic merging of ‘compatible’ LSPs –e.g. same ERO Merging is ‘voluntary’ - can disable Sources initiate LSPs, control compatibility Input welcome