Information About LISP Reliable Registration
LISP Reliable Map Registration
LISP ETR periodically sends UDP based map registration message to map server. This results in control traffic and scalability problems. TCP based reliable map registration or LISP reliable map registration mechanism is developed as an enhancement and replacement to the UDP based map registration mechanism.
The LISP reliable map registration mechanism as shown in the figure is described below:
ETR sends UDP based map registration message to map server.
Map server processes map registration and sends map-notify to ETR. This message serves as acknowledgment.
ETR initiates a TCP session with map-server using three-way handshake.
When TCP based map registration is not supported by map server then ETR uses UDP based map registration to establish a session with the map server.
Once the TCP session is established, map-server sends a registration refresh message to the ETR.
ETR sends map registrations to the map server through the TCP connection.
Map server acknowledges for the map registrations.
There are no configuration commands for this feature. This feature is turned on automatically.
Verifying the LISP Reliable Registration
Perform this task to verify the LISP Reliable Registration feature which is enabled automatically in the LISP network. In this example, a LISP site uses a single edge router that functions as both ITR and ETR (known as an xTR). Routing Locators (RLOCs) are in IPv4. EID prefixes are in both IPv4 and IPv6. The LISP site registers to two map server/map resolver (MSMR) devices in the network core. The topology used in verifying LISP Reliable Registration is as shown in the figure below.
The components as shown in the topology are described below:
- xTR1 and xTR2 are xTRs for 2 LISP sites.
- Core1 and Core 2 are routing locators (RLOCs) core routers with no LISP configuration.
- New MSMR is a map-server and map-resolver with reliable map-registration support, whereas Old MSMR does not support reliable map-registration.
- PxTR1 works as a Proxy Ingress Tunnel Router (PITR) and Proxy Egress Tunnel Router (PETR) between the network with 10.0.0.0/8 prefix and the LISP sites.
- Only static routing protocols are used in this setup to reduce control traffic.
In the following output, a ‘#’ sign in the ‘Up’ column indicates reliable map registration session.
Device# show lisp site LISP Site Registration Information * = Some locators are down or unreachable # = Some registrations are sourced by reliable transport Site Name Last Up Who Last Inst EID Prefix Register Registered ID A never no -- 0.0.0.0/0 01:59:44 yes# 203.0.113.11 10.10.10.0/24 01:59:44 yes# 203.0.113.11 10.20.20.0/24 01:59:44 yes# 203.0.113.11 172.16.0.0/24 01:59:44 yes# 203.0.113.11 2001:DB8::/32 B never no -- 0.0.0.0/0 never no -- 10.0.0.0/8 01:59:43 yes# 198.51.100.21 10.30.30.0/24 01:59:43 yes# 198.51.100.21 10.40.40.0/24 never no -- 126.96.36.199/8 01:59:43 yes# 198.51.100.21 188.8.131.52/24 01:59:43 yes# 198.51.100.21 2001:DB8::/48
In the following output, no ‘#’ sign in the ‘Up’ column indicates that the Old MSMR does not support reliable map registration.
Device# show lisp site LISP Site Registration Information * = Some locators are down or unreachable Site Name Last Up Who Last Inst EID Prefix Register Registered ID A never no -- 0.0.0.0/0 00:00:00 yes 203.0.113.11 172.16.0.0/24 00:00:55 yes 198.51.100.21 184.108.40.206/24 00:00:03 yes 203.0.113.11 2001:DB8::/32 B never no -- 10.0.0.0/8 00:00:00 yes 203.0.113.11 10.10.10.0/24 00:00:00 yes 203.0.113.11 10.20.20.0/24 00:00:55 yes 198.51.100.21 10.30.30.0/24 00:00:55 yes 198.51.100.21 10.40.40.0/24 00:00:52 yes 198.51.100.21 2001:DB8::/48
The following output is from xTR1 that uses 2 map servers. Reliable map-registration session is established with 220.127.116.11 (New MSMR), but not with 18.104.22.168 (Old MSMR).
Device# show lisp session Sessions for VRF default, total: 2, established: 1 Peer State Up/Down In/Out Users 22.214.171.124 Up 05:05:40 6/3 2 126.96.36.199 Down never 0/0 1
The following output is from New MSMR. It has established reliable map-registration sessions with two ETRs.
Device# show lisp session Sessions for VRF default, total: 2, established: 2 Peer State Up/Down In/Out Users 203.0.113.11 Up 05:19:53 3/6 1 198.51.100.21 Up 05:18:28 2/5 1