diff --git a/draft-ietf-lsvr-l3dl.xml b/draft-ietf-lsvr-l3dl.xml index 8b0052d..9fa4373 100644 --- a/draft-ietf-lsvr-l3dl.xml +++ b/draft-ietf-lsvr-l3dl.xml @@ -98,17 +98,12 @@ The Massive Data Center (MDC) environment presents unusual problems of scale, e.g. O(10,000) forwarding devices, while its homogeneity presents opportunities for simple approaches. - Approaches such as "Jupiter Rising: A study of non-blocking switching networks" [PAYWALLED] - use a + Approaches such as use a central controller to deal with scaling, while BGP-SPF provides massive scale-out without centralization using a tried and tested scalable distributed control plane, offering a scalable routing solution in - - "Clos Networks" - + and similar environments. But BGP-SPF and similar higher level device-spanning protocols, e.g. , need logical link @@ -119,12 +114,12 @@ Layer-3 Discovery and Liveness (L3DL) provides brutally simple mechanisms for devices to Discover each other's unique endpoint identification, - Discover mutually supported layer-3 encapsulations, e.g. - IP/MPLS, - Discover Layer-3 IP and/or MPLS addressing of interfaces of the - encapsulations, + Discover mutually supported layer-3 and layer-2.5 + encapsulations, e.g. IP/MPLS, + Discover Layer-3 IP and/or layer-22.5 MPLS addressing of + interfaces of the encapsulations, Present these data, using a very restricted profile of a BGP-LS - API, to BGP-SPF which computes the + API, to BGP-SPF which computes the topology and builds routing and forwarding tables, Enable Layer-3 link liveness such as BFD, Provide Layer-2 keep-alive messages for session continuity, @@ -163,7 +158,7 @@ A mechanism by which link-state and TE information can be collected from networks and shared with external components using the BGP routing protocol. See . + target="RFC9552"/>. A hybrid protocol using BGP transport but a Dijkstra Shortest Path First decision process. See . @@ -194,7 +189,7 @@ Protocol Data Unit, an L3DL application layer message. A PDU's content may need to be broken into multiple Datagrams to make it through MTU or other restrictions. - An 32-bit identifier unique in the + An 32-bit identifier unique in the current routing domain, see . An established, via OPEN PDUs, session between two L3DL capable link end-points, @@ -228,8 +223,6 @@ assumed. Familiarity with BGP-SPF, , might be useful. - L3DL assumes a new IEEE assigned EtherType (TBD). - The number of addresses of one Encapsulation type on an interface link may be quite large given a TOR with tens of servers, each server having a few hundred micro-services, resulting in an @@ -237,9 +230,10 @@ migration can cause serious address prefix disaggregation, resulting in interfaces with thousands of disaggregated prefixes. - Therefore the L3DL protocol is session oriented and uses - incremental announcement and withdrawal with session restart, a la - BGP (). + To provide the scalability, reliability, ordering, etc. for the + above, the L3DL protocol is session oriented and uses incremental + announcement and withdrawal with session restart, a la BGP (). @@ -249,11 +243,11 @@ Devices discover each other on logical links Logical Link Endpoint Identifiers (LLEIs) are exchanged Layer-2 Liveness checks may be started - Encapsulation data are exchanged and IP-Level Liveness checks + Encapsulation data are exchanged and layer-3 Liveness checks enabled - A BGP-like upper layer protocol is assumed to use the - identifiers and encapsulation data to discover and build a topology - database + A BGP-like upper layer protocol (BGP-SPF in this example) is + assumed to use the identifiers and encapsulation data to discover + and build a topology database
@@ -286,13 +280,14 @@ There are two protocols, the inter-device (left-right in the diagram) per-link layer-3 discovery and the API to the upper level - BGP-like routing protocol (up-down in the above diagram): + (BGP-SPF in this example) routing protocol (up-down in the above + diagram): - Inter-device PDUs are used to exchange device and logical link - identities and layer-2.5 (MPLS) and 3 identifiers (not payloads), - e.g. device IDs, port identities, VLAN IDs, Encapsulations, and IP - addresses. + Inter-device PDUs are used to exchange device/system and + logical link identities (see ) and layer-2.5 + (MPLS) and 3 identifiers (not payloads), e.g. device IDs, port + identities, VLAN IDs, Encapsulations, and IP addresses. A Link Layer to BGP API presents these data up the stack to a BGP protocol or an other device-spanning upper layer protocol, @@ -300,11 +295,14 @@ - The upper layer BGP family routing protocols cross all the - devices, though they are not part of these L3DL protocols. + L3DL assumes a new IEEE assigned EtherType (TBD). - To simplify this document, Layer-2 framing is not shown. L3DL is - about layer-3. + The upper layer BGP family routing protocols cross all the + devices, though they are not part of the L3DL protocol. + + To simplify this document, Layer-2 framing is not shown. + Ethernet framing is extremely well documented elsewhere, see ). @@ -316,6 +314,9 @@ on such a topology, and only on a multi-link topology, send periodic HELLOs forever, see . + Devices may be directly connected or through an intermediate + device, see . + Once a new device is recognized, both devices attempt to negotiate and establish a session by sending unicast OPEN PDUs () to the source MAC addresses (plus VIDs if @@ -324,10 +325,10 @@ target="afisafi"/>) configured on an end point may be announced and modified. Note that these are only the encapsulation and addresses configured on the announcing interface; though a device's loopback - and overlay interface(s) may also be announced. When two devices on - a link have compatible Encapsulations and addresses, i.e. the same - AFI/SAFI and the same subnet, the link is announced via the BGP-LS - API. + and any pseudo/overlay interface(s) may also be announced. When two + devices on a link have compatible Encapsulations and addresses, + i.e. the same Encapsulation and the same subnet, the link is + announced via the BGP-LS API.
@@ -337,11 +338,11 @@ the identities of logical link endpoint(s) reachable from a Logical Link Endpoint, . - The HELLO and OPEN, , PDUs, which are used - to discover and exchange detailed Logical Link Endpoint - Identifiers, LLEIs, and the ACK/ERROR PDU, are mandatory; other - PDUs are optional; though at least one encapsulation SHOULD be - agreed at some point. + The HELLO , and OPEN, , PDUs, which are used to discover and exchange + detailed Logical Link Endpoint Identifiers, LLEIs, and the + ACK/ERROR PDU, are mandatory; other PDUs are optional; though at + least one encapsulation SHOULD be agreed at some point. The following is a ladder-style diagram of the L3DL protocol exchanges: @@ -670,7 +671,7 @@ uint32_t sbox_checksum_32(const uint8_t *b, const size_t n) Endpoint Identifiers, LLEIs. An LLEI is a variable length descriptor which could be an ASN, a - classic RouterID, a catenation of the two, an eight octet ISO System + classic Router ID, a catenation of the two, an eight octet ISO System Identifier , or any other identifier unique to a single logical link endpoint in the topology. @@ -1774,7 +1775,7 @@ uint32_t sbox_checksum_32(const uint8_t *b, const size_t n)
- BGP-LS defines BGP-like Datagrams + BGP-LS defines BGP-like Datagrams describing logical link state (links, nodes, link prefixes, and many other things), and a new BGP path attribute providing Northbound transport, all of which can be ingested by upper layer @@ -2499,7 +2500,7 @@ uint32_t sbox_checksum_32(const uint8_t *b, const size_t n) - + @@ -2553,9 +2554,16 @@ uint32_t sbox_checksum_32(const uint8_t *b, const size_t n) - + 802.3-2018 - IEEE Standard for Ethernet + + IEEE + + + +