Last Modified: 2003-01-14
The products of this working group will be:
o A set of requirements for mechanisms to logically separate the control and data forwarding planes of an IP network element (NE)
o An applicability statement for the ForCES model and protocol
o Informational RFCs as necessary documenting current approaches to the functional model and controlled objects therein
o An architectural framework defining the entities comprising a ForCES network element and identifying the interactions between them.
o A description of the functional model of a Forwarding Element
o A formal definition of the controlled objects in the functional model of a forwarding element. This includes IP forwarding, IntServ and DiffServ QoS. An existing specification language shall be used for this task.
o Specification of IP-based protocol for transport of the controlled objects. When the control and forwarding devices are separated beyond a single hop, ForCES will make use of an existing RFC2914 compliant L4 protocol with adequate reliability, security and congestion control (e.g. TCP, SCTP) for transport purposes.
The main focus area of the working group will be control and forwarding separation for IP forwarding devices where the control and forwarding elements are in close (same room/small number of hops) or very close (same box/one hop) proximity. Other scenarios will be considered but at not the main focus of the work. The functional model of the forwarding element will include QoS (DiffServ and IntServ) capabilities of modern networking devices such as routers. In order to minimize the effort to integrate forwarding elements and control elements, a mechanism for auto discovery and capability information exchange will form an integral part of the standardized interface.
ForCES will coordinate with other standards bodies and working groups as appropriate. Examples of such bodies include IETF/GSMP, IETF/Megaco, the Network Processing Forum (NPF), the Multiservice Switching Forum (MSF), IEEE P1520, and SoftSwitch. ForCES will review relevant protocol efforts such as GSMP and Megaco and will extend or reuse them if appropriate. If protocol reuse is accepted as satisfactory for fulfilling the ForCES requirements then ForCES may recharter to adopt specific deliverables around the selected protocol.
| MAY 02 | Submit requirements document to IESG | |
| JUL 02 | Submit framework document to IESG | |
| NOV 02 | Submit forwarding element functional model document to IESG | |
| NOV 02 | Submit formal definition of controlled objects in functional model | |
| MAR 03 | Submit protocol selection/definition document to IESG | |
| MAR 03 | Submit applicability statement to IESG |
work.IETF 56, ForCES Meeting Minutes About 100 persons attended the meeting. Thanks to Hormuzd for taking notes. FACT - Ram Gopal Ram presented a protocol overview including the NE model and the message structure, Q Adam - why CE tag if one CE is active? A Ram - cause of multiple CE sets He then showed message classes and the types. Afterwards the association phase including the sequence of operations were shown. Also the states of the elements were introduces. Q Jamal - Is this CE-to-CE or FE-to-FE communication? A Ram - NO, CE-to-FE. Then the normal operation phases were given. Finally some other features were given like 2 phase, command bundling, and high availability (HA). Q XYZ - Can this be used only for post-association? A Ram - yes, but certain configuration needs to be done in pre-association Q Adam - All IP Address are only 32 bits, is that on purpose? A Ram - No, this need to be fixed Netlink2 - Robert Haas The reasoning why Netlink2 is derived from netlink is because netlink is already widely used in linux systems as a message-based interface between control code (usually running in user space) and forwarding code (kernel space) to perform, for instance, IP routing, ARP, QoS, etc. Netlink2 extends netlink to address the fact that CEs and FEs can be distributed. The Netlink2 header is an extension of the netlink header with slight changes, and supports optional TLVs. FEs and CEs have unique PIDs. Logical PIDs can be used to group FEs and CEs. Netlink2 extends the concept of the netlink wire to Netlink2 wires and bundles that are built with IP unicast and multicast addresses to enable scalability and high-availability. Q XYZ - How do multiple CEs send messages to multiple FEs? A Robert by different multicast addresses Netlink2 has built in reliability, it has a prioritization method, an ACK strategy to confirm messages. It support atomicity, ordering and batching. The flexibility of Netlink2 comes from its wires & bundles. In the current version of the draft there is no capability discovery yet. Q Alex - The draft does not seem to give specifics about configurations. Lots of should/could but no details ? A Jamal - last section talks about this, the draft gives mechanisms, need to add details Q Alex - What about Scalability issues? A Jamal - by using broadcast and multicast Q Lorenzo Vicisano (co-chair of reliable multicast WG) - Scalability might be limited by reliability A Robert - reliable multicast methods from this WG should be used if needed. FE Model - Ram Gopal Ram showed the FE Block and the block library. On the Issue list he had - topology discovery out of scope, no restriction of FE block layout, control of topology CE or FE? The intend is to provide a bunch of handles and do not represent topology. Q XYZ - what do you mean by logical loops & physical loops? A Ram - physical - layout of board, logical - blocks can have some logic Q Jamal - looping to same instance should be allowed A Ram - yes, this depends on the block properties Q Joel - describe blocks on wire and in doc and need input from WG Q Jamal - no constraint on how many FE blocks can be connected, add some text for this. Q Chair - Has the doc been read? A Quite a few people have read the draft but more people should be involved. Chair - Should further discuss the draft on the mailing list TIPC (Telecom Inter Process Communication) - Jon Maloy TIPC is high-speed, reliable message oriented communication service specially designed for cluster environments. They implemented the FACT proposal on top of TPIC and using XML encoding. The protocol has a logical addressing scheme and agile connections. It was claimed that TIPC is easily portable. It runs on different interconnects (over Ethernet, UDP/IP, SCTP/IP). Q Alex - Why TIPC over SCTP, it is already a transport? Q - how does TIPC addressing work on IP? Q - is it used most of the time over Ethernet or over IP ? A Jon - over Ethernet, Q - then why 2 addressing schemes? A - for logical addressing TIPC is location transparent, and FE binds to services. At the start of the synchronization the topology detection takes place. Q Jamal - is this built into TIPC ? or in lower transport ? A Jon - yes Demo of FACT/XML over 2 P4 systems Q Alex - what is the latency of the switch? A Jon - currently 1 sec Q Jamal - how big is this protocol? Would it fit on top of a router? A Jon - code size is 15,000 loc Q - why is it inside the kernel? A - for performance reasons |