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How to use UBR10k as DHCP server to provision CM's


This is a feature example where in smaller size or test bench deployments, UBR10K CMTS itself can be configured to provision a bunch of cable modems.


UBR10K CMTS, Cable Modems, and appropriate RF Connections. 


There are few bare minimum DHCP options required to provision a cable modem.
1. IP Address (yiaddr in DHCP header)
This defines the scope of IP Addresses to be assigned to CM’s.

2. Subnet Mask (DHCP Option 1)
Subnet Mask

3. Local Time offset (DHCP Option 2)
This defines timing offset, (-88hr = -28800sec = ffff.8f80)

4. Default Router  (DHCP Option 3)
Default gateway IP for CM

5. Time of Day server IP Address (DHCP Option 4)
ToD TDT Service for CM

6. Log server (DHCP Option 7)
Log server IP to keep log records.

7. TFTP Server IP Address (DHCP Option 7)
TFTP Server IP where modem’s boot file is present.

8. Name of DOCSIS modem Boot Config file.
Name of modem’s boot config file.

9. Least time.
DHCP Lease time.

DHCP Lease time.Configurations

Step 1. Log in to CMTS, and create a IP DHCP Pool for CM
RP-CMTS(config)# ip dhcp pool TEST ß This is name of Pool

Step 2.
RP-CMTS(dhcp-config)# network 
This specifes range of IP Address

Step 3.
This specifes boot file name

Step 4.
RP-CMTS(dhcp-config)#  next-server

This specifes TFTP server IP

Step 5.
RP-CMTS(dhcp-config)# default-router

This specifes default gateway IP

Step 6.
RP-CMTS(dhcp-config)#  option 7 ip

This specifes Log server

Step 7.
RP-CMTS(dhcp-config)#  option 4 ip
This specifes ToD server IP

Step 8.
RP-CMTS(dhcp-config)#  option 2 hex ffff.8f80
This specifes Timing offset in seconds

Step 9.
RP-CMTS(dhcp-config)#  lease 1 0 10
This specifes lease time 1day 0hrs 10min

Next configuration portion covers how to create modem config file

Step 10.
RP-CMTS(config-file)# cable config-file
This specifes modem config file name.

Step 11.
RP-CMTS(config-file)# service-class 1 max-upstream 100000
This specifes max upstream limits

Step 12.
RP-CMTS(config-file)# service-class 1 guaranteed-upstream 1000
This specifes class of service

Step 13.
RP-CMTS(config-file)# service-class 1 max-burst 1600
This specifes max burst size.

Step 14.
RP-CMTS(config-file)# cpe max 2
This specifes max CPE’s allowed behind CM

Step 15.
RP-CMTS(config-file)# timestamp
This specifes inclusion of timestamp.

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