Junos OS

Hi,

When executing command

clear dhcp server binding 10.0.1.5

In most cases lease is not fade away immediatly and time varies from 5 to 7 minutes to completly remove lease.

10.0.1.5     132696869   00:0f:ea:5e:28:8d  363         RELEASE    ae0.3222028424

The maximum lease time is 10 minutes. All leases are subscriber manager clients so the network-services enhanced-ip turned on.

rfc3203 doesn't turned on

> show configuration system services dhcp-local-server 
traceoptions { ## Warning: 'traceoptions' is deprecated
    file dhcp.log size 5m files 5;
}
pool-match-order {
    external-authority;
    ip-address-first;
}
overrides {
    client-discover-match;
}
group internet {
    authentication {
        password coolPassw0rd;
        username-include {
            delimiter "@";
            mac-address;
            option-82 circuit-id remote-id;
        }
    }
    dynamic-profile dhcp-local-server-profile;
    access-profile external-radius;
    interface ae0.0;
    interface ae1.0;
    interface ae2.0;
    interface ae3.0;
}

Hi !

RELEASE is a valid state. It means that client is releasing the IP. Means MX is waiting for an ACK from client that the IP is rleased and can be assigned it to someone esle. 

• RELEASE—Client is releasing IP address lease.

It mostly depends on the router/ device that is getting the DHCP IP.

you can do "monitor traffic interface <> deatail" to see what is happeninging once you issue the command to clear binding.  

Regards

Arpit 

I know that it is valid state but I can not understand why time varies so much.

I was trying to disable vlan facing BRAS so all clients cannot reach device but it shows different release times.

Thank for explanation,  I'll try to test with "well known" client router.

Hi!

Just to add "remove-when-no-subscribers" removes the VLAN once all the subscribers under the VLAN has been logged out. 

https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/remove-when-no-subscribers-edit-interfaces-auto-configure.html

But in our case the IP itself is not released so subscriber is still online as per BRAS. 

May be you can collect following :

- Log out  the subscriber.

Monitor the following : 

 1) show subscriber extensive (check if its not in terminating for long time, if its in terminating then its probably JUNOS who is taking time)

2) show interface <subscriber interface> .Check if the traffic (in/out packets are inccreasing)

3)  "monitor traffic interface <> deatail" .Do this for both subscriber interface , VLAN interface and the IFD (xe- or ge- or ae- interfae) 

Also share your config if possible.

(Note : Kudos are always appreciated)

Regards

Arpit 

Thanks for your reply,

I can share config it's not a secret:

> show configuration interfaces ae20
flexible-vlan-tagging;
auto-configure {
    vlan-ranges {
        dynamic-profile vlan-autosense-profile {
            accept dhcp-v4;
            ranges {
                3-942;
                944-4094;
            } } }
    remove-when-no-subscribers;
}
encapsulation flexible-ethernet-services;
aggregated-ether-options {
    load-balance {
...

Remove when no subscribers is turned on.

By the way I am using single vlan tagging not stacked vlans model.

I'll do testing what you proposed to me and share results (I should select time to not disturb my customers too much), thanks.

Because I'm not using QinQ scheme I've clear all dhcp addresses in vlan.

Thaere are up to 6 addresses stuck in RELEASE state.

Monitor traffic with

monitor traffic interface demux0.3221368208 detail    

shows nothing.

Next command shows

show interfaces ae20.3221367934 

That some input/output packets counters are raising.

Attachment(s)

lease_slow.txt   8 KB 1 version

Hi Schadel !

       I was under the impression that ae20.3221367934 is your subscriber interface but it seems that this is the vlan interface. 

       And the subscriber inteave is demux0.3XXXXXXX.

      (Please confirm if my understanding is correct or not)      

      Please attach the complete configuration , it seems that somethings are messed up. 

    Also please share :

show subscriber extensive interface <ae20.3221367934 or similar>

show subscriber extensive interface <demux0.3XXXXXXX >

Regards

Arpit 

Hi,

Yes you are absolutely right, this dynamic interface binded to one vlan.

And I've included BRAS part of the configuration.

Thanks in advance.

Attachment(s)

show_ifs.txt   2 KB 1 version

jun_bras_config.txt   3 KB 1 version

Hi !

 Thanks for sharing the data !

Your config looks fine. I'm worndering that its the 3 service profiles that are taking some time in clean up. 

For Data points , please try the following :

(1) Logout a subscriber using "clear dhcp server binding <>" and collect following multiple time till the subscriber is gone :

show subscribers extensive <>

show network-access aaa subscribers username <username> (you will get the user from "show subscribers extensive" >

show network-access aaa subscribers session-id detail <session-id> (you will get the session id from "show subscribers extensive" >

(2) also try clearing a user IP using the follwing command :

clear network-access aaa subscriber username <username >

OR

clear network-access aaa subscriber session-id <session-id>

Now check the binding and see if it cleared soon or not ?

Regards

Arpit 

During maintanance window I've done test you have told me.

All my service stuch in Service State: SvcVolAcctFinalWait

Looks like accounting is a problem, am I right?

Full listing in attachment file.

Attachment(s)

long_dhcp_clear.txt   11 KB 1 version

Its not actually accounting problem , it seems that process is taking some time to clean up multiple service session attached to this subscriber. 

Once susbcriber is logged out ; accounting stop is send to radius (for each service session) and a response is required for MX (for each service session) to clean the subscriber.

Not sure why its taking this much time.

Please file a JTAC case to get this investigated.

Regards

Arpit