DHCP Configuration Example in Nokia 7750 SR Router

This article will show you how to configure DHCP for Nokia Router 7750 includes basic DHCP Relay and DHCP Server configurations. The article is presented in a technical style that is easy to understand and simple. You can download the simulation at the end of the article.

DHCP Server Configuration in Nokia 7750 SR Router

We configure the DHCP Server with the following parameters:

• DHCP Server Name: AdminReboot
• Pool name: POOL1
• Subnet: 192.168.1.0/24
• Default-Gateway: 192.168.1.1
• Allocation address range: 192.168.1.10 to 192.168.1.100
• Use GI address matching

A:DHCP-Server# configure router dhcp
            local-dhcp-server "AdminReboot" create
                use-gi-address
                pool "POOL1" create
                    subnet 192.168.1.0/24 create
                        options
                            default-router 192.168.1.1
                        exit
                        address-range 192.168.1.10 192.168.1.100
                    exit
                exit
                no shutdown
            exit

Select DHCP Server for the interface to PE2:

A:DHCP-Server# configure router interface "to-PE2" 
            address 10.0.1.2/24
            port 1/1/4
            local-dhcp-server "AdminReboot"
            no shutdown

DHCP Relay Configuration in Nokia 7750 SR Router

On CE, create epipe 36, having on spoke-sdp to PE1, and a SAP to Client (p1/1/1) who is need an IP address via DHCP.

A:CE# configure service epipe 36 
            sap 1/1/1 create
                no shutdown
            exit
            spoke-sdp 36:36 create
                no shutdown
            exit
            no shutdown

On PE1, create VPLS 36, having a spoke-sdp to CE.

A:PE1# configure service vpls 36 
            allow-ip-int-bind
            exit
            spoke-sdp 36:36 create
                no shutdown
            exit
            no shutdown

On PE1, create VPRN 35, RD = 65555:35, RT: target:65555:35, having one interface receiving VPLS 36 as a sap, configure DPCP relay point to PE2.

A:PE1# configure service vprn 35 
            interface "to-VPLS" create
                address 192.168.1.1/24 #IP Address of Gateway
                dhcp
                    server 10.0.1.2 #IP of DHCP Server
                    trusted
                    gi-address 192.168.1.1 #Gateway IP Address
                    no shutdown
                exit
                vpls "36" #Routed-VPLS
                exit
            exit
            bgp-ipvpn
                mpls
                    auto-bind-tunnel
                        resolution any
                    exit
                    route-distinguisher 65555:35
                    vrf-target target:65555:35
                    no shutdown
                exit
            exit
            no shutdown               

On PE2, create VPRN 35, RD = 65555:35, RT: target:65555:35, and having one interface to DHCP server (P1/1/4).

A:PE2# configure service vprn 35 
A:PE2>config>service>vprn# info 
----------------------------------------------
            interface "to-DHCP-Server" create
                address 10.0.1.1/24
                sap 1/1/4 create
                exit
            exit
            bgp-ipvpn
                mpls
                    auto-bind-tunnel
                        resolution any
                    exit
                    route-distinguisher 65555:35
                    vrf-target target:65555:35
                    no shutdown
                exit
            exit
            no shutdown

Check the DHCP results with the debug command

Configure DHCP debugging for router 7750 device as follows:

A:DHCP-Server# show debug 
debug
    router "Base"
        local-dhcp-server "AdminReboot"
            detail-level medium
            mode egr-ingr-and-dropped
        exit
    exit
exit

To save the debug information in memory and display it after using the show log command, we configure the following:

A:DHCP-Server# configure log log-id 88 
            from debug-trace
            to memory
            no shutdown

After the client receives the ip, we show debug on the DHCP Server:

A:DHCP-Server# show log log-id 88 

===============================================================================
Event Log 88 log-name 88
===============================================================================
Description : (Not Specified)
Memory Log contents  [size=100   next event=6  (not wrapped)]

5 2021/08/02 01:40:43.409 UTC MINOR: DEBUG #2001 Base DHCP server
"DHCP server:  AdminReboot 
Tx DHCP Ack to relay agent at 192.168.1.1 vrId=1

   ciaddr: 192.168.1.11      yiaddr: 192.168.1.11
   siaddr: 10.0.1.2          giaddr: 192.168.1.1
   chaddr: 00:50:79:66:68:05    xid: 0xb2c06a57

   DHCP options:
   [53] Message type: Ack
   [54] DHCP server addr: 10.0.1.2
   [51] Lease time: 864000
   [1] Subnet mask: 255.255.255.0
   [3] Router: 192.168.1.1
   [12] Host name: VPCS
   [255] End                          
"

So the client received the ip 192.168.1.11. To check the how many used and remaining IP number, use the following command:

A:DHCP-Server# show router dhcp local-dhcp-server "AdminReboot" summary 
...
-------------------------------------------------------------------------------
Subnet                 Free     %    Stable   Declined Offered  Rem-pend Drain
-------------------------------------------------------------------------------
192.168.1.0/24         89       97%  2        0        0        0        N

Totals for pool        89       97%  2        0        0        0        
-------------------------------------------------------------------------------

Totals for server      89       97%  2        0        0        0        
...

More information about DHCP configuration in 7750 SR router can be found on Nokia Document. If you have any questions or discussions, you can leave a comment below the article. Thank you.