Hello, everyone!
Today, I will show you basic commands for configuration DHCP relay on the OLT. There are a few commands for configuration.
In this example, we have one server group 1, this group contains
one DHCP server. It works in active mode, and its IP address is
X.X.80.10. The max response time is 20 s, and max count of response
timeout is 10. For services HSI, VoIP, IPTV and MNG, we use different
VLANs (HSI – vlan100, VoIP – vlan200, IPTV – vlan300, and MNG –
vlan400). And we have defined VLAN interfaces for all of these
services. And the end, we have to bind server group 1 to users in
VLANs (with the IP address of the L3 interface).
1. Command for configuring the DHCP forwarding mode:
TEST(config)#dhcp mode layer-3 standard
Configuration mode can be:
Layer-2 mode is used by OLT for transparently transmission packets and it doesn`t process these packets.
Layer-3 is used for forwarding packets. This mode can be:
mac range – in this mode, DHCP server selects according MAC range,
option60 – DHCP server selects according option60 domain, and
standard – DHCP server selects according to interface.
We choose layer-3 standard, because we want to forward packets according interface.
2. Command for setting network parameters of DHCP server group:
TEST(config)#dhcp-server1 ipX.X.80.10
The first part of command, dhcp-server, is a command for creating DHCP server group.
This number 1 in command is the number of DHCP server groups. This number can be from 0 to 19. And after that, we have to put IP address of this DHCP server group.
In our case, we have one DHCP server, and because of that, we put the number 1 for DHCP server group and one IP address for this DHCP server. This IP address must be the same as the IP address of the DHCP server on the network side.
3. Command for setting the working mode of the DHCP server
TEST(config)#dhcp server mode backup 20 10
There are two modes:
backup. With this mode, the system can send packets from users only to the current active DHCP server.
shareload. In this mode, the system can send packets from users to both the active and standby servers.
Number 20 in this command indicates a maximum response time, it is 20s. The next number is 10 and it is the maximum count of response timeout.
4. Commands for defining VLAN interfaces and binding for server group
TEST(config)#interface vlanif X
TEST(config-if-vlanifX)#ip address X.X.1.2 X.X.255.0
TEST(config-if-vlanifX)#dhcp-server 1
With the last commands, we defined VLAN interfaces for all of services – HSI, VoIP, IPTV and MNG. After that, we have to bind server group 1 to users in VLANs.
After that, we have to configure DHCPoption82, because DHCP protocol is not secure. I will explain DHCPoption82 in one of the next articles.
Thank you!
