diff --git a/draft-ymbk-idr-l3-discovery.xml b/draft-ymbk-idr-l3-discovery.xml index f7e0f84..b551148 100644 --- a/draft-ymbk-idr-l3-discovery.xml +++ b/draft-ymbk-idr-l3-discovery.xml @@ -440,73 +440,6 @@ -
- - L3BND discovers neighbors on logical links and establishes - sessions between the two ends of all consenting discovered logical - links. A logical link is described by a pair of Logical Link - 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 - Identifier , or any other identifier unique - to a single logical link endpoint in the topology. - - An L3BND deployment will choose and define an LLEI which suits its - needs, simple or complex. Examples of two extremes follow: - - A simplistic view of a link between two devices is two ports, - identified by unique MAC addresses, carrying a layer-3 protocol - conversation. In this case, the MAC addresses might suffice for the - LLEIs. - - Unfortunately, things can get more complex. Multiple VLANs can - run between those two MAC addresses. In practice, many real devices - use the same MAC address on multiple ports and/or - sub-interfaces. - - Therefore, in the general circumstance, a fully described LLEI - might be as follows: - -
- - 0 1 2 3 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| | -+ System Identifier + -| | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| ifIndex | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - -
- - System Identifier, a la , is an eight - octet identifier unique in the entire operational space. Routers - and switches usually have internal MAC Addresses which can be padded - with high order zeros and used if no System ID exists on the device. - If no unique identifier is burned into a device, the local L3BND - configuration SHOULD create and assign a unique one, likely by - configuration. - - ifIndex is the SNMP identifier of the (sub-)interface, see . This uniquely identifies the port. - - For a layer-3 tagged sub-interface or a VLAN/SVI interface, - IfIndex is that of the logical sub-interface, so no further - disambiguation is needed. - - L3BND PDUs learned over VLAN-ports may be interpreted by upper - layer-3 routing protocols as being learned on the corresponding - layer-3 SVI interface for the VLAN. - - LLEIs are big-endian. - -
-
The HELLO PDU is unique in that it is encapsulated in a multicast @@ -594,6 +527,17 @@
+ The HOWDY PDU is identical in format to the HELLO PDU except it + is sent unicast. + + The unicast source address is that of the interface responding to + the HELLO multicast PDU, and the AFI MUST be the same as the HELLO + to which it is responding. + + The receiver knows it is a HOWDY because it is unicast and the + destination address is the source address of the HELLO sent by the + receiver of the HOWDY. + @@ -602,7 +546,7 @@ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -| PDU Type = 1 | Payload Length = 0 | +| PDU Type = 0 | Payload Length = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+ @@ -610,6 +554,25 @@
+
+ + With the HELLO/HOWDY exchange, both sides have agreed on an AFI + and each other's IP address in that AFI. This is sufficient to open + a TCP session between them, which will allow for very large data + PDUs while obviating the need to invent complex transports. + + As the HELLO/HOWDY exchange was extremely sparse, the peers could + not yet have agreed on security data for authentication. This will + be done in the OPEN exchange. If the OPEN exchange agrees on an + authorization mechansim and keys, then this TCP session MUST be + closed, and a new TLS session with the newly agreed credentials MUST + opened, see . + + If the TCP open fails, then this SHOULD be logged and the parties + MUST go back to the initial state and try HELLO/HOWDY. + +
+
Each device has learned the other's MAC Address from the HELLO @@ -654,7 +617,7 @@ needed to prevent session closure due to a repeated OPEN caused by a race or a dropped or delayed ACK. - My LLEI is the sender's LLEI, see . + My LLEI is the sender's LLEI, see xref target="llei". AttrCount is the number of attributes in the Attribute List. Attributes are single octets the semantics of which are @@ -753,6 +716,19 @@
+
+ + With the OPEN exchange, both sides MAY have agreed on the + credentials and methods to move from naked TCP to TLS. If so, + the initial TCP session is closed and a TLS session between the same + two parties is negotiated and opened. + + If the Naked TCP close fails or the TLS negotiation is + unsuccessful, then this SHOULD be logged and the parties MUST go + back to the initial state and try HELLO/HOWDY. + +
+