Requirements for Signaling of (Pre-) Congestion Information DiffServ Domain

1. Requirements for Signaling of (Pre-) Congestion Information DiffServ Domain draft-karagiannis-pcn-signaling-requirements-01 Georgios Karagiannis, Tom Taylor, Kwok Chan, Michael Menth

2. Outline • Goal of draft (changed based on comments) • PCN content (changed based on comments) • Requirements for signaling between PCN-egress-nodes and decision point (changed based on comments) • Requirements for signaling between decision point and PCN-ingress-node (changed based on comments) • Next steps

3. Goal of draft • briefly describe PCN content and specifies requirements to be satisfied by signaling protocol needed to transport this PCN content between: • (1) PCN-egress-nodes and decision point • (2) PCN-ingress-nodes and decision point • note that when decision point coincides with PCN-ingress-node then the information exchanges are internal operations • signalling requirements derived from CL and SM edge behaviour drafts

4. PCN content (1) • PCN egress feedback: • Rate: content measured and reported by the PCN-egress-node to the decision point where it is used to make flow admission control and flow termination decisions: • rate of not-marked PCN traffic • rate of threshold marked PCN traffic, which applies only to CL edge behaviour • rate of excess-traffic-marked PCN traffic • reported in octets/s at the end of each measurement interval

5. PCN content (2) • Optional: List with flow IDs of received excess-traffic-marked flows (CL only): • sent when multipath routing is enabled; • sent only when excess-traffic-marking observed; • hence has to be sent reliably (not included in current version of draft).

6. PCN content (3) • ingress rate request: • message sent by the decision point towards the PCN-ingress-node to request PCN-ingress-node to measure and report value of the rate of admitted PCN traffic for a given ingress-egress-aggregate

7. PCN content (4) • PCN ingress feedback: • content measured and reported by the PCN-ingress-node to the decision point where it is used to make flow termination decisions: • rate of admitted PCN traffic • reported in octets/s to decision point as soon as possible after receiving ingress rate request from decision point • Action item: • Make sure the behaviour drafts specify that that measurement results from PCN-ingress-node are based on data captured following receipt of ingress rate request.

8. Requirements for signaling between PCN-egress-nodes and decision point • PCN Reporting Frequency • PCN egress feedback can be reported at regular intervals, in order 100ms to 500ms • Signaling requirements: • Priority of signaling messages: • signaling messages SHOULD have a higher priority than data packets; • Local information exchange: • signaling messages MUST be able to carry PCN contents from PCN-egress-node to decision point; • Carry identification of PCN edge nodes: • signaling protocol MUST be able to carry identification (address information) of PCN edge nodes;

9. Requirements for signaling between PCN-egress-nodes and decision point • Signaling requirements (cont.): • Carry identification of ingress-egress-aggregates: • Signaling protocol MUST be able to carry (address information) of ingress-egress-aggregates), i.e., addresses of PCN-ingress-node and PCN-egress-node between which they pass; • Signaling load: • load generated by signaling protocol to carry PCN content from PCN-egress-nodes to decision point SHOULD be minimized as much as possible; • Reliability: • There are situations that PCN contents need to be sent in a reliable way, meaning that PCN-egress-node MUST be acknowledged that sent PCN content is successfully received by the PCN-ingress-node; • it is considered that the PCN egress feedback that is sent regularly SHOULD NOT be sent reliably. • List with flow IDs of received excess-traffic-marked flows is not sent regularly, hence SHOULD be sent reliably (not included in current version draft)

10. Requirements for signaling between PCN-egress-nodes and decision point • Signaling requirements (cont.): • Security requirements (not included in current version draft): • Message authentication • attacker could cause denial of service using impersonation • Message integrity • attacker could cause denial of service by modifying message contents • No requirement seen for confidentiality

11. Requirements for signaling between PCN-egress-nodes and decision point • Filter specifications (all or subset of following): • source IP address; • destination IP address; • protocol identifier and higher layer (port) addressing; • flow label (typical for IPv6); • SPI field for IPsec encapsulated data; • DSCP/TOS field; • IP address of PCN-ingress-node; • IP address of PCN-egress-node; • IP address of decision point (not needed, it will be removed from next version draft)

12. Requirements for signaling between PCN-ingress-nodes and decision point • PCN Reporting Frequency • PCN content (“ingress rate request” and PCN ingress feedback) sent between decision point and PCN-ingress-node are not sent on a regular fashion. • Signaling requirements • same signaling requirements applied between PCN-egress-node and decision point apply for signaling between decision point and PCN-ingress-node, with exception: • “ingress rate request” and “PCN ingress feedback” MUST be sent reliably, since they are not sent regularly

13. Next steps • We ask the support of the PCN working group such that the signaling requirements draft becomes a PCN working group draft.