DHCP Relay Limit Reached, Limiting to only 170 VLANs on a VSP 8600

[Anonymous]

Hi,

Have hit an issue with a VSP8600 hitting the limit set in regards to how many DHCP relay forwarding addresses are allowed, which is 1024.

The DHCP configuration has been configured providing DHCP relay addresses per VLAN. The list varies per VLAN, from 6 to 2 address.

Doing some calculations, say there was 6 forwarders per VLAN, something like the below could be quite plausible:

• DHCP Server 1
• DHCP Serve 2
• SCCM Server 1
• SCCM Server 2
• NAC Server 1
• NAC Server 2

Using that format, at just 170 VLANs you would bust the limit. Even if I reduced it too four you would still bust the limit at 256 VLANs, which seems exceedingly low!

In this particular case I am converting from EOS to VOSS, which uses the same method of configuration but EOS didn’t any limitation concerns.

In EXOS as another example, you can just configure the 6 individual relay addresses and configure which VLANs to use it. You also have the flexibility of defining what VLANs use what forwarders, thereby essentially reducing the 1024 forwarder addresses to just 6.

So I see a few options:

1. Maybe something similar is available in VOSS as in EXOS, where I could potentially configure just 4 or 6 forwarders instead of separately for each VLAN?
2. Flex the dimensions of the switch
3. Somehow reduce the number of forwarders
4. Have been suggested to split forwarders addresses so server 1 addresses on core 1 and server 2 addresses on core 2?

Currently running the recommended VOSS version of 6.3.2.0

Here is an example of the DHCP relay configuration:

int vlan 2
ip address 10.133.174.2/24
ip directed-broadcast enable
ip dhcp-relay 
ip dhcp-relay mode dhcp 
exit
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.6 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.24 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.215 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.249 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.201 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.91 enable
ip dhcp-relay fwd-path 10.133.174.2 10.133.80.93 enable
int vlan 10
ip address 192.168.45.2/29
ip directed-broadcast enable
ip dhcp-relay 
ip dhcp-relay mode dhcp 
exit
ip dhcp-relay fwd-path 192.168.45.2 10.133.124.91 enable
ip dhcp-relay fwd-path 192.168.45.2 10.133.124.93 enable

Many thanks in advance.