DHCPv4 offer selection parameters on a subscriber group-interface DHCP relay

With the configuration of a discover-delay, the forwarding of a DHCP Discover Message to the DHCP server is delayed, which results in a delayed DHCPv4 Offer to the DHCP client. A discover-delay (in deciseconds) can be configured for DHCP Discover messages, as shown in the following examples:

originated by DHCP clients with odd or even MAC addresses

dhcp
    server 192.0.2.1
    offer-selection
        client-mac odd
            discover-delay 5
        exit
    exit
    no shutdown
exit

sent to a specific DHCP server (a delay for up to eight servers can be configured)

dhcp
    server 192.0.2.1 192.0.2.2
    offer-selection
        server 192.0.2.2
            discover-delay 5
        exit
    exit
    no shutdown
exit

for which no per client MAC or per DHCP server discover-delay is configured (for example, a default discover-delay)
```
dhcp
    server 192.0.2.1
    offer-selection
        discover-delay 5
    exit
    no shutdown
exit
```

Additional considerations:

Configuring a per DHCP server discover-delay and a per DHCP client MAC address discover-delay is mutually exclusive.
A default discover-delay can be combined with either a per DHCP server or a per DHCP client MAC delay.
When a new Discover message, such as a retransmitted message is received from the same client while a discover-delay timer is running, the discover-delay timer is stopped, the queued Discover message is discarded, and the new Discover message is immediately forwarded without delay.