DHCP problem: Huawei GPON

[human_exe]

Community,

I keep getting DHCP issues on wireless clients, is anyone experienced in this kind of topology?

That CORE device is a Huawei S5720-36C.

There is an Inter-VLAN PROXY ARP configuration to separate clients, phones, access points, cameras, each type on a different VLAN ID.

I have an MS120-24P with a few MR, but DHCP issues are not happening there, wondering what I could check to get the DHCP running.

Clients join the SSID and take forever to get an IP, sometimes it just displays Failed to Obtain IP.

It is important to say CORE runs its own DHCP, so packets go through this one to get to my MX DHCP.

What would you check first?

Thanks in advance,

[human_exe]

NOTE:

MX DHCP handles MR and wireless clients
CORE S5720-36C DHCP handles phones, cameras, etc.

[ww^]

Check the scope for free addresses.

Make packet captures in your network and analyze them to help find where the problem is

[Philip D'Ath]

I'm not familiar with Huawei, but some GPON kit I have used was hard work. They just don't work like normal Ethernet networks.

Do you have to use inter-vlan proxy arp? Can you not just use standard layer 3 routing?

[Brandon Svec]

Many years ago I recall having really slow DHCP like you explain to IP phones off traditional Cisco switches sometimes. I learned before even understanding why to apply a command, spanning-tree portfast that would fix it.

Here is something about it: https://community.cisco.com/t5/switching/spanning-tree-dhcp/td-p/1398109

Maybe your issue is is similar on the core switch?

[human_exe · Accepted solution]

Okay, after a lot of troubleshooting, it was the GPON configuration, the way it handles DHCP was delaying the IP leases, these Huawei had a default configuration on them.

I had no access to that network, so I had them in the middle, between my MX and MR devices.

Thanks, all.

[DelmasEric]

Hello,

It looks I have same issue with Huawei OLT and HDCP request.

Do you remember what was the default configuration on the OLT which caused the defect?

Regards