Cisco Locator ID Separation Protocol (LISP)

This topic is to discuss the following lesson:

Hello Mr Molenaar is there any way that you could attach a small lab with this Lesson
Regards Evan-

Hello Evan,

I will add a walkthrough of the configuration soon. I didn’t do it right away because the CCNP ENCOR exam only covers LISP in theory.

If you want to take a look at a working lab, I have the configs of the topology that I used in this explanation:

Here are the configs:

hostname H1
!
no ip routing
!
interface GigabitEthernet0/1
 ip address 192.168.1.101 255.255.255.0
!
ip default-gateway 192.168.1.254
!
end
hostname H2
!
no ip routing
!
interface GigabitEthernet0/1
 ip address 192.168.2.102 255.255.255.0
!
ip default-gateway 192.168.2.254
!
end
hostname XTR1
!
interface LISP0
!
interface GigabitEthernet0/1
 ip address 192.168.123.1 255.255.255.0
!
interface GigabitEthernet0/2
 ip address 192.168.1.254 255.255.255.0
!
router lisp
 locator-set SITE1
  192.168.123.1 priority 10 weight 10
  exit
 !
 database-mapping 192.168.1.0/24 locator-set SITE1
 ipv4 itr map-resolver 192.168.123.3
 ipv4 itr
 ipv4 etr map-server 192.168.123.3 key MY_SECRET
 ipv4 etr
 exit
!
end
hostname XTR2
!
interface LISP0
!
interface GigabitEthernet0/1
 ip address 192.168.123.2 255.255.255.0
!
interface GigabitEthernet0/2
 ip address 192.168.2.254 255.255.255.0
!
router lisp
 locator-set SITE2
  192.168.123.2 priority 10 weight 10
  exit
 !
 database-mapping 192.168.2.0/24 locator-set SITE2
 ipv4 itr map-resolver 192.168.123.3
 ipv4 itr
 ipv4 etr map-server 192.168.123.3 key MY_SECRET
 ipv4 etr
 exit
!
end
hostname MR-MS
!
interface GigabitEthernet0/1
 ip address 192.168.123.3 255.255.255.0
!
router lisp
 site SITE1
  authentication-key MY_SECRET
  eid-prefix 192.168.1.0/24
  exit
 !
 site SITE2
  authentication-key MY_SECRET
  eid-prefix 192.168.2.0/24
  exit
 !
 ipv4 map-server
 ipv4 map-resolver
 exit
!
end

Some commands you might want to try:

  • show ip lisp
  • show lisp site
  • show ip lisp map-cache
  • debug lisp control-plane all

Once I work on the CCIE Enterprise material, I’ll create a full walkthrough for this.

Rene

Thank you Rene for the info and lab, I have to re-certify for CCNP by May 31. BTW your website is outstanding.

Best Regards Evan-

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Hi Rene:
Thanks for sharing this LISP topic. I would like to know how does H1 at site 1 knows the address of H2 in site2 in the first place? ( Is it same as ARP request / response?). In that case the ARP packet also goes through the same encapsulation process ?
Thanks
Rama

Hello Ramakrishnan

H1 knows the address of H2, in most cases, simply because a user has input it. For example, if H2 is an email server, then the email client of H1 has been manually configured to reach that email server. If H2 is a web server, then H1 has used a DNS lookup service for www.ip-address-of-h2.net, for example, and resolved the destination address for that host.

Note also that LISP is a feature that interconnects subnets. What I mean is, the gateways of both H1 and H2 are found within their local LISP sites. This means that Layer 2 protocols such as ARP remain within the local sites. Only routing functions operate between LISP sites and the RLOC space. So you would never see ARP requests traversing the RLOC space.

I hope this has been helpful!

Laz

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Thanks Lagapides for the prompt reply. I will read through and will update if I have any more questions.

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