Application Layer Multicast Extensions to RELOAD draft-kolberg-sam-baseline-protocol-01 Mario Kolberg, University of Stirling, UK (Editor) John Buford, Avaya Labs Research, USA Thomas C. Schmidt, HAW Hamburg Matthias Waehlisch, link-lab & FU Berlin

Overview Baseline document –Extension to RELOAD, uses P2PSIP RELOAD as the overlay layer –Uses AMT (Automatic IP Multicasting Tunneling) for tunneling between ALM and Native Multicast regions –Main change: updated Section 4 (Hybrid ALM tree operations) –Editorial changes throughout Request that the RG adopt this as an RG deliverable for future RFC submission Any comments welcome!

Multicast Widely considered important for consumer communications applications –Small group video conferencing –IPTV Native multicast deployment is rather slow Alternatives: –Application Layer Multicast –Native Multicast with tunnelling between regions SAM RG within IRTF investigates a third option: –Hybrid protocols which use overlay multicast with native multicast where it is available

Select between OM subtree and NM subtree opportunistically Expect improved network efficiency, increase throughput and reduce latency Design based on AMT tunnelling mechanism Protocol uses structured P2P overlay to connect peers in different types of multicast regions Hybrid Overlay Multicast Assumption: All tree member nodes are part of the overlay AMT-R(elay): features a NM multicast connection to the multicast backbone AMT-GW: does not have multicast connection to multicast backbone – uses an AMT-R to connect to the backbone

Example ALM-NM Toplogy

Sec. 4.1 Algorithm: ALM only groupID=create(); –Allocation of unique groupID –Out of band advertisement/publishing in DHT joinTree(groupID) –Out of band discovery of groupID (lookup in DHT) –Send join message to peer with the nearest NodeID to the groupID (tree root) –Peers on the path to the root join tree as forwarding nodes leaveTree(groupID) –Sends leave message to each child node and the parent node –If parent is a forwarding node and this is its last child, forward to its parent –Child node receiving a leave message from parent sends join message to tree root multicastMsg(groupID) –SSM tree: creator of tree is source; it sends data message to tree root from where it will be forwarded down the tree –ASM: peer sending message will send it to its parent and children; each node receiving message will forward it to remaining tree edges it is connected to

Sec. 4.2 Algorithm: ALM with peer at AMT site Joining peer is within an AMT region with AMT-GW (P21) and uses ALM algorithm to try to connect to tree Following cases are possible depending on which nodes respond: –NM peer in the tree which is in the same NM region as the joining peer. The joining peer uses ALM routing or connects directly to the NM peer. –NM peer which is in another NM region which supports an AMT-R (P6 and P7) or another peer which can function as a P-AMT-R (P-AMT-R17), the joining peer can use AMT to connect to one of the NM peers. –There is no NM peer in the tree. The NM peer uses ALM routing.

Sec. 4.3 ALM with NM peer using AMT-R Joining peer is within an AMT region with AMT-R (P6) and uses ALM algorithm to try to connect to tree Following cases are possible depending on which nodes respond: –NM peer in the tree which is in the same NM region as the joining peer (P7). The joining peer uses ALM routing or connects directly to the NM peer. –NM peer in the tree which is in a different NM region as the joining peer (such as P16). The joining peer can use AMT to connect to one of the NM peers. –peer in the tree which can function as P-AMT-GW (P-AMT-GW11). The NM peer can join the tree using ALM or connecting to the P-AMT-GW via its local AMT-R. –peer in the tree which is in an AMT-GW region (P21). The NM peer can join the tree using ALM or connecting to the peer via the AMT-GW and its local AMT-R. –There is no NM peer in the tree. The NM peer uses ALM routing.

Sec 5. Group Management API API between Application and Group stack Objectives: –Common multicast API for transparent communication in underlay and overlay –Abstract naming to support different distribution technologies –Access to different multicast flavours → Details in subsequent presentation

Sec. 6 Protocol definition Messages between RELOAD nodes Checked against the latest RELOAD draft, and no changes to messages required Supports different tree formation algorithms described earlier Control messages are propagated using overlay routing Message categories –ALM Usage: Tree life-cycle (create, join, leave, re-form, heartbeat) –Hybrid ALM Usage: Tree life-cycle AMT gateway advertisement and discovery Peer region and multicast properties

V02 Changes Being Discussed Move section 7 up just behind section 4 and reflect the achievable operations directly in reload usages.

RG Action Requested Request that the RG adopt this as an RG deliverable for future RFC submission Comments welcome