LISP is a network protocol and architecture that creates two separate address spaces: the RLOC space, and the EID space. Multiple EID spaces are connected to a common RLOC space. Ingress and Egress Tunnel Routers (ITR/ETR) separate the EID space from the RLOC space. A device that is both an ITR and an ETR is called an xTR. LISP xTR devices create a tunnel across the RLOC space to transport traffic between two EID spaces.
This mechanism is made possible by a central registry which enables the LISP Mapping Service. It consists of a Map-Server and a Map-Resolver (MS/MR). A single device can maintain both functions. Essentially, each xTR informs the MS/MR through Map-Register messages about the locally connected EID Host prefixes. As a result, the MS/MR knows which Host is connected to which xTR as described below.
1) Map-Register Host prefixes, sent by each xTR device to the MS/MR informing about connected Host addresses. The MS/MR creates an EID-to-RLOC xTR address mapping entry, and a database is built with mapping entries (similar to DNS records).
2) Encapsulated Map-Request, sent by the xTR to the MS/MR requesting information about an EID-to-RLOC xTR address mapping. It asks about which xTR has a specific EID Host prefix assigned.
3) Map-Reply to Map-Request is sent by the xTR that has the destination EID Host prefix assigned, and it is sent to the requesting xTR router, so now the two xTR devices can build a LISP tunnel across the RLOC space to transfer traffic between EID sites.
What are the main components of LISP?
The following table lists important components of the LISP network architecture.
Main components of LISP network
Function
Description
Ingress Tunnel Router (ITR)
A router that receives traffic from hosts in the EID space, and sends traffic into the RLOC space. This router encapsulates traffic in a LISP tunnel by creating an extra IP header.
Egress Tunnel Router (ETR)
A router that receives traffic from an ITR in the RLOC space, and sends traffic into the EID space towards hosts. This router decapsulatas traffic by removing the extra IP header.
Map-Server (MS)
A mapping database, a registry of EID-to-RLOC entries, a device that contains a list of EID prefixes that are associated with an RLOC.
Map-Resolver (MR)
A device that receives the Encapsulated Map-Request messages from ITR routers. Can be the same device as the MS.
Map-Cache
Similar to a routing table, the map-cache is maintained on the xTR and includes information received in a Map-Reply about a destination EID-to-RLOC mapping.
Proxy ITR / Proxy ETR
A PITR/PETR device connects the LISP network (RLOC/EID spaces) to a non-LISP network. If the PITR/PETR functions are combined in a single device it is called a PxTR.
Configuring LISP with three EID subnets
In the following example topology the hosts are located in the LISP EID space using the instance-ID 10. This is important because the LISP instance-ID needs to match on the xTR routers and also on the MS/MR. The two sites (EID space) are connected through the RLOC space. The RLOC space uses the underlay network protocol IS-IS to ensure each router can be reached using its Loopback IP address. Alternatively, the underlay protocol OSPF could have also been used.
The xTR routers handle ingress and egress traffic between the RLOC space and the EID space. Traffic that enters the RLOC space is encapsulated with an extra IP header including a LISP header. In this particular topology an extra 32-bits of information are added in the RLOC space due to the LISP encapsulation. These 32-bits are added to each ICMP packet as they are transfered between the xTR routers R1 and R5.
Regarding the configuration, the xTR and the MS/MR authenticate each other with the pre-shared key p4ssw0rd.123. The EID space host IP subnets are statically mapped to the xTR through which they are reachable. LISP Map-Register messages are sent by the xTR to inform the MS/MR about xTR-to-EID prefix bindings. As a result, the MS/MR can be queried to locate EID host prefixes and their associated RLOC xTR.
Configuration:
R1 (xTR)
R1#show run int Lo10 | sec int
interface Loopback10
ip address 1.1.1.1 255.255.255.255
R1#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW1 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW1 in VLAN 10 **
encapsulation dot1Q 10
ip address 192.168.1.2 255.255.255.0
R1#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to SW2 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/1.20 | sec int
interface GigabitEthernet0/1.20
description ** to SW2 in VLAN 20 **
encapsulation dot1Q 20
ip address 192.168.2.2 255.255.255.0
R1#show run int Gi0/2 | sec int
interface GigabitEthernet0/2
description ** to R2 **
ip address 10.1.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R1#show run | sec ^router lisp
router lisp
eid-table default instance-id 10
database-mapping 192.168.1.0/24 1.1.1.1 priority 1 weight 100
database-mapping 192.168.2.0/24 1.1.1.1 priority 1 weight 100
ipv4 itr map-resolver 6.6.6.6
ipv4 itr
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
ipv4 etr
exit
!
exit
R1#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0001.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R5 (xTR)
R5#show run int Lo10 | sec int
interface Loopback10
ip address 5.5.5.5 255.255.255.255
R5#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW3 **
no ip address
duplex auto
speed auto
media-type rj45
R5#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW3 in VLAN 30 **
encapsulation dot1Q 30
ip address 192.168.3.2 255.255.255.0
R5#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to R4 **
ip address 10.4.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R5#show run | sec ^router lisp
router lisp
eid-table default instance-id 10
database-mapping 192.168.3.0/24 5.5.5.5 priority 1 weight 100
ipv4 itr map-resolver 6.6.6.6
ipv4 itr
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
ipv4 etr
exit
!
exit
R5#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0005.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R6 (MS/MR)
R6#show run int Lo10 | sec int
interface Loopback10
ip address 6.6.6.6 255.255.255.255
R6#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to R3 **
ip address 10.5.0.2 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R6#show run | sec ^router lisp
router lisp
site Site1
authentication-key p4ssw0rd.123
eid-prefix instance-id 10 192.168.1.0/24
eid-prefix instance-id 10 192.168.2.0/24
exit
!
site Site2
authentication-key p4ssw0rd.123
eid-prefix instance-id 10 192.168.3.0/24
exit
!
ipv4 map-server
ipv4 map-resolver
exit
R6#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0006.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R2
R2#show run int Lo10 | sec int
interface Loopback10
ip address 2.2.2.2 255.255.255.255
R2#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to xTR R1 **
ip address 10.1.0.2 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R2#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to R3 **
ip address 10.2.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R2#show run | sec ^router
router isis
net 49.0010.0000.0000.0002.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R3
R3#show run int Lo10 | sec int
interface Loopback10
ip address 3.3.3.3 255.255.255.255
R3#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to R2 **
ip address 10.2.0.2 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R3#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to R4 **
ip address 10.3.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R3#show run int Gi0/2 | sec int
interface GigabitEthernet0/2
description ** to R6 **
ip address 10.5.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R3#show run | sec ^router
router isis
net 49.0010.0000.0000.0003.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
SW1
SW1#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to Host1 **
switchport access vlan 10
switchport mode access
negotiation auto
SW1#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to xTR R1 **
switchport trunk allowed vlan 10
switchport trunk encapsulation dot1q
switchport mode trunk
negotiation auto
Host1
Host1#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW1 **
ip address 192.168.1.1 255.255.255.0
duplex auto
speed auto
media-type rj45
Host1#show run | sec ^ip route
ip route 0.0.0.0 0.0.0.0 192.168.1.2
Host1#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 7/7/8 ms « Host1 can reach Host3Host2#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 6/7/9 ms « Host2 can reach Host3Host2#trace 192.168.3.1 probe 1
Type escape sequence to abort.
Tracing the route to 192.168.3.1
VRF info: (vrf in name/id, vrf out name/id)
1 192.168.2.2 3 msec
2 *
3 *
4 *
5 *
6 192.168.3.1 6 msec « Traceroute reaches Host3 but no replies in betweenR1#show lisp session
Sessions for VRF default, total: 1, established: 1
Peer State Up/Down In/Out Users
6.6.6.6Up 01:00:10 5/2 1 « LISP session between the xTR and the MS/MRR6#show lisp instance-id 10 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
Site1 01:00:54 yes# 1.1.1.1 10 192.168.1.0/24« Site EID prefix in MS/MR database with assigned xTR
01:00:54 yes# 1.1.1.1 10 192.168.2.0/24
Site2 01:01:03 yes# 5.5.5.5 10 192.168.3.0/24R6#show lisp instance-id 10 site rloc members« This output shows the Loopback IP address of the xTR routers reachable in the RLOC space
LISP RLOC Membership for router lisp 0 IID 10
Entries: 2 valid / 2 total, Distribution disabled
RLOC Origin Valid
1.1.1.1 Registration Yes
5.5.5.5 Registration Yes
R1#show ip lisp map-cache instance-id 10« This output functions similar to a routing table
LISP IPv4 Mapping Cache for EID-table default (IID 10), 2 entries
0.0.0.0/0, uptime: 01:06:38, expires: never, via static send map-request « If no match, then xTR queries the MS/MR for EID to RLOC mapping
Negative cache entry, action: send-map-request
192.168.3.0/24, uptime: 01:06:18, expires: 22:53:41, via map-reply, complete « Host 3 prefix received with query/reply process
Locator Uptime State Pri/Wgt
5.5.5.5 01:06:18 up 1/100
R5#show ip lisp map-cache instance-id 10
LISP IPv4 Mapping Cache for EID-table default (IID 10), 3 entries
0.0.0.0/0, uptime: 01:06:44, expires: never, via static send map-request
Negative cache entry, action: send-map-request
192.168.1.0/24, uptime: 01:06:38, expires: 22:53:21, via map-reply, complete
Locator Uptime State Pri/Wgt
1.1.1.1 01:06:38 up 1/100
192.168.2.0/24, uptime: 01:06:34, expires: 22:53:25, via map-reply, complete
Locator Uptime State Pri/Wgt
1.1.1.1 01:06:34 up 1/100
When a packet sent by Host1 is destined to Host3, the xTR router R1 encapsulates it. On R1, LISP adds an additional IP header to the existing IP packet. This extra IP header routes the packet to the correct xTR R5 where the destination EID address of Host3 can be found.
Configuring PxTR to connect LISP and non-LISP site
In the following example scenario, Site 1 is a LISP EID space, and Site 2 is a non-LISP site. This means, Site 2 does not run the LISP protocol, it is an external domain, for example it could be a public network like the internet. The translation between the two domains (LISP and non-LISP) is done on the PxTR router R5. R5 is designated as the PxTR in the LISP network so an EID prefix that does not have a specific RLOC xTR assigned will be routed to the PxTR.
The following are important aspects when configuring communication between a LISP and a non-LISP network.
PxTR R5 is configured on the xTR R1 with the command ipv4 use-petr 5.5.5.5
PxTR needs to know how to reach the MS/MR, the command ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123 is added on R5
PxTR will query the MS/MR for EID prefixes, so the MS/MR needs to have EID-to-RLOC mappings for Site 1
Configuration:
R1 (xTR)
R1#show run int Lo10 | sec int
interface Loopback10
ip address 1.1.1.1 255.255.255.255
R1#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW1 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW1 in VLAN 10 **
encapsulation dot1Q 10
ip address 192.168.1.2 255.255.255.0
R1#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to SW2 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/1.20 | sec int
interface GigabitEthernet0/1.20
description ** to SW2 in VLAN 20 **
encapsulation dot1Q 20
ip address 192.168.2.2 255.255.255.0
R1#show run int Gi0/2 | sec int
interface GigabitEthernet0/2
description ** to R2 **
ip address 10.1.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R1#show run | sec ^router lisp
router lisp
eid-table default instance-id 10
database-mapping 192.168.1.0/24 1.1.1.1 priority 1 weight 100
database-mapping 192.168.2.0/24 1.1.1.1 priority 1 weight 100
ipv4 use-petr 5.5.5.5
ipv4 itr map-resolver 6.6.6.6
ipv4 itr
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
ipv4 etr
exit
!
exit
R1#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0001.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R5 (PxTR)
R5#show run int Lo10 | sec int
interface Loopback10
ip address 5.5.5.5 255.255.255.255
R5#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW3 **
no ip address
duplex auto
speed auto
media-type rj45
R5#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW3 in VLAN 30 **
encapsulation dot1Q 30
ip address 192.168.3.2 255.255.255.0
R5#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to R4 **
ip address 10.4.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R5#show run | sec ^router lisp
router lisp
eid-table default instance-id 10
map-cache 0.0.0.0/0 map-request
ipv4 proxy-etr
ipv4 proxy-itr 5.5.5.5
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
exit
!
exit
R5#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0005.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R6 (MS/MR)
R6#show run int Lo10 | sec int
interface Loopback10
ip address 6.6.6.6 255.255.255.255
R6#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to R3 **
ip address 10.5.0.2 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R6#show run | sec ^router lisp
router lisp
site Site1
authentication-key p4ssw0rd.123
eid-prefix instance-id 10 192.168.1.0/24
eid-prefix instance-id 10 192.168.2.0/24
exit
!
ipv4 map-server
ipv4 map-resolver
exit
R6#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0006.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
Host1#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 7/7/8 ms « LISP site can reach non-LISP siteHost2#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 7/8/10 ms
R1#show ip lisp map-cache instance 10
LISP IPv4 Mapping Cache for EID-table default (IID 10), 2 entries
0.0.0.0/0, uptime: 00:07:46, expires: never, via static send map-request
Negative cache entry, action: send-map-request
192.168.3.0/24, uptime: 00:07:34, expires: 00:07:25, via map-reply, forward-native « Site 2 (non-LISP) prefix is learned on xTR R1Encapsulating to proxy ETR« The destination RLOC address is the PxTR R5
To make the communication work, PxTR R5 queries the MS/MR for the LISP EID prefix of Host1. This is encapsulated in a Map-Request message and is shown in the following packet capture. The Map-Reply is visible in the next frame (number 7), and it arrives directly from the xTR R1. As a result, PxTR R5 can populate its local map-cache.
The following output is taken from the PxTR R5 and shows the map-cache entries for the EID prefixes of Host1 and Host2. These addresses have been received with Map-Reply messages from the xTR R1.
R5#show ip lisp map-cache instance 10
LISP IPv4 Mapping Cache for EID-table default (IID 10), 3 entries
0.0.0.0/0, uptime: 00:26:52, expires: never, via static send map-request
Negative cache entry, action: send-map-request
192.168.1.0/24, uptime: 00:26:05, expires: 23:33:54, via map-reply, complete
Locator Uptime State Pri/Wgt
1.1.1.1 00:26:05 up 1/100
192.168.2.0/24, uptime: 00:26:01, expires: 23:33:58, via map-reply, complete
Locator Uptime State Pri/Wgt
1.1.1.1 00:26:01 up 1/100
Configuring dynamic EID to enable host mobility
In the following example scenario, the hosts in the EID space are dynamically registered on the MS/MR by the xTR routers. When a host initiates traffic, the xTR sends a Map-Register message to the MS/MR about the associated EID prefixes. In turn, the MS/MR device replies with a Map-Notify message to the xTR confirming that the EID prefix is received. Meanwile, the MS/MR installs a dynamic EID mapping record into its local registry, associating it with the sending xTR. Note the MS/MR uses a more specific /32 subnet mask (instead of a /24) to install dynamic entries.
Configuration:
R1 (xTR)
R1#show run int Lo10 | sec int
interface Loopback10
ip address 1.1.1.1 255.255.255.255
R1#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW1 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW1 in VLAN 10 **
encapsulation dot1Q 10
ip address 192.168.1.2 255.255.255.0
lisp mobility EXAMPLE-DYNAMIC-EID1
R1#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to SW2 **
no ip address
duplex auto
speed auto
media-type rj45
R1#show run int Gi0/1.20 | sec int
interface GigabitEthernet0/1.20
description ** to SW2 in VLAN 20 **
encapsulation dot1Q 20
ip address 192.168.2.2 255.255.255.0
lisp mobility EXAMPLE-DYNAMIC-EID2
R1#show run int Gi0/2 | sec int
interface GigabitEthernet0/2
description ** to R2 **
ip address 10.1.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R1#show run | sec ^router lisp
router lisp
locator-set EXAMPLE-LOCATOR-SET
IPv4-interface Loopback10 priority 1 weight 100
exit
!
eid-table default instance-id 10
dynamic-eid EXAMPLE-DYNAMIC-EID1
database-mapping 192.168.1.0/24 locator-set EXAMPLE-LOCATOR-SET
exit
!
dynamic-eid EXAMPLE-DYNAMIC-EID2
database-mapping 192.168.2.0/24 locator-set EXAMPLE-LOCATOR-SET
exit
!
ipv4 itr map-resolver 6.6.6.6
ipv4 itr
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
ipv4 etr
exit
!
exit
R1#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0001.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R5 (xTR)
R5#show run int Lo10 | sec int
interface Loopback10
ip address 5.5.5.5 255.255.255.255
R5#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to SW3 **
no ip address
duplex auto
speed auto
media-type rj45
R5#show run int Gi0/0.10 | sec int
interface GigabitEthernet0/0.10
description ** to SW3 in VLAN 30 **
encapsulation dot1Q 30
ip address 192.168.3.2 255.255.255.0
lisp mobility EXAMPLE-DYNAMIC-EID
R5#show run int Gi0/1 | sec int
interface GigabitEthernet0/1
description ** to R4 **
ip address 10.4.0.1 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R5#show run | sec ^router lisp
router lisp
locator-set EXAMPLE-LOCATOR-SET
IPv4-interface Loopback10 priority 1 weight 100
exit
!
eid-table default instance-id 10
dynamic-eid EXAMPLE-DYNAMIC-EID
database-mapping 192.168.3.0/24 locator-set EXAMPLE-LOCATOR-SET
exit
!
ipv4 itr map-resolver 6.6.6.6
ipv4 itr
ipv4 etr map-server 6.6.6.6 key p4ssw0rd.123
ipv4 etr
exit
!
exit
R5#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0005.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
R6 (MS/MR)
R6#show run int Lo10 | sec int
interface Loopback10
ip address 6.6.6.6 255.255.255.255
R6#show run int Gi0/0 | sec int
interface GigabitEthernet0/0
description ** to R3 **
ip address 10.5.0.2 255.255.255.252
ip router isis
duplex auto
speed auto
media-type rj45
isis circuit-type level-2-only
isis network point-to-point
R6#show run | sec ^router lisp
router lisp
site Site1
authentication-key p4ssw0rd.123
eid-prefix instance-id 10 192.168.1.0/24 accept-more-specifics
eid-prefix instance-id 10 192.168.2.0/24 accept-more-specifics
exit
!
site Site2
authentication-key p4ssw0rd.123
eid-prefix instance-id 10 192.168.3.0/24 accept-more-specifics
exit
!
ipv4 map-server
ipv4 map-resolver
exit
R6#show run | sec ^router isis
router isis
net 49.0010.0000.0000.0006.00
is-type level-2-only
advertise passive-only
metric-style wide
log-adjacency-changes
passive-interface Loopback10
Host1#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 7/7/8 ms « Host1 can reach Host3R6#show lisp site name Site1 instance-id 10 | sec 192.168.1.1/32
EID-prefix: 192.168.1.1/32 instance-id 10
First registered: 00:10:31
Last registered: 00:10:27
Routing table tag: 0
Origin: Dynamic, more specific of 192.168.1.0/24 « Host1 prefix dynamically learned on MS/MR
Merge active: No
Proxy reply: No
TTL: 1d00h
State: complete
Registration errors:
Authentication failures: 0
Allowed locators mismatch: 0
ETR 1.1.1.1, last registered 00:10:27, no proxy-reply, map-notify
TTL 1d00h, no merge, hash-function sha1, nonce 0x47E81530-0x542282D3
state complete, no security-capability
xTR-ID 0x54C78800-0xF4038DDC-0x0B03474E-0x434CF153
site-ID unspecified
sourced by reliable transport
Locator Local State Pri/Wgt Scope
1.1.1.1 yes up 1/100 IPv4 none
R6#show lisp site name Site2 instance-id 10 | sec 192.168.3.1/32
EID-prefix: 192.168.3.1/32 instance-id 10
First registered: 00:04:05
Last registered: 00:04:01
Routing table tag: 0
Origin: Dynamic, more specific of 192.168.3.0/24
Merge active: No
Proxy reply: No
TTL: 1d00h
State: complete
Registration errors:
Authentication failures: 0
Allowed locators mismatch: 0
ETR 5.5.5.5, last registered 00:04:01, no proxy-reply, map-notify
TTL 1d00h, no merge, hash-function sha1, nonce 0xF8F1534B-0x0A4B6BAA
state complete, no security-capability
xTR-ID 0x7219E18C-0xC343F1FB-0xBC48AB8F-0x2AF4E544
site-ID unspecified
sourced by reliable transport
Locator Local State Pri/Wgt Scope
5.5.5.5 yes up 1/100 IPv4 none
R1#show ip lisp map-cache instance-id 10
LISP IPv4 Mapping Cache for EID-table default (IID 10), 4 entries
0.0.0.0/0, uptime: 00:19:37, expires: never, via static send map-request
Negative cache entry, action: send-map-request
192.168.1.0/24, uptime: 00:19:37, expires: never, via dynamic-EID, send-map-request « Learned through dynamic EID configuration
Negative cache entry, action: send-map-request
192.168.2.0/24, uptime: 00:19:37, expires: never, via dynamic-EID, send-map-request
Negative cache entry, action: send-map-request
192.168.3.1/32, uptime: 00:04:55, expires: 23:55:04, via map-reply, complete « After Map-Request, prefix learned through Map-Reply
Locator Uptime State Pri/Wgt
5.5.5.5 00:04:55 up 1/100 « xTR R5 is the associated RLOC router
When dynamic EID prefixes are configured the xTR sends a Map-Register message to the MS/MR. The following packet capture shows a Map-Register message originated by the xTR R1 containing a dynamic EID /32 prefix in Site 1.
Packet capture comparing Map-Register messages
The following packet capture shows a Map-Register message sent with a static EID prefix mapping record (not dynamic). When compared to the dynamic EID mapping record shown above (in previous section), it is visible that different prefix lengths are used. Notably, the Map-Register message sent during dynamic EID registration uses a /32 prefix.
For this reason, the MS/MR device needs the command eid-prefix instance-id 10 192.168.1.0/24 accept-more-specifics with the "accept-more-specifics" keyword added when dynamic EID prefixes are configured.
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