[kea-dev] : New member in the community

sunil mayya sunilmayya at gmail.com
Mon May 7 23:24:42 UTC 2018


Hello Dev Team

I am Sunil Mayya, studying in TU Kaiserslautern, Germany working as GSoC
intern for ISC. I am very excited to part of the ISC team.

I am still new to the project,  in the next few  months you might get lot
of questions, so kindly bear with me :). I want to be associated with the
community for long term and have a lot of learning along the way.

I had a few doubts regarding implementing multiple IP address for a single
IA to support renumbering.

Basic questions
1. From code I understand host reservations are indexed using DUID, mac
addr and ID.  Do we need host reservation defined for every other client
for assigning IP addresses to the client ? I understand although IP
addresses are not defined  in  host reservation it will be picked from the
pool.

The below is a typical procedure how the admin would follow after
implementing this feature.
I seek your opinion on *each* of the step . This mechanism is in its after
discussing with Tomek .  I am skipping the RKAP part as most of it was
clear during earlier discussion.

1. Admin shall first update the configuration. The new configuration shall
contain-
{ Old subnet,  *reduced* lifetime,  host reservation* client_id1*{old_ip1}
} *and* {new subnet, lifetimes,  host reservation* client_id1*{new ip1}

2. Admin sends a Reconfigure message via command line interface.
Reconfigure message can contain Options to prompt client to send
Information Request , Renew , Rebind. This shall be *decided by the admin
through command l*ine interface. I am not sure how server could handle
adding which option  to be included as this is configuration dependent.
 e.g. If the DNS/NTP servers are changed in the network admin could use the
option prompting the user to send the Information request message.
 Initially during my proposal I had thought this could be done based on
status of the lease but I think it does not makes sense anymore.

3. Decrease the valid and preferred lifetime of the existing IPv6
address/prefix in a IA_NA/IA_PD
How - Fetched from the update the system configuration for the
 client/subnet with a reduced valid lifetime and preferred life time .
Typically  T1 < T2  < pref < valid. But it our case it should be   pref <
valid < T1 < T2.  *Decrease the existing lease *time for the corresponding
IP.(Let the admin  handle configuring the lifetimes).

4. Include new address/prefix in the same IA_NA/IA_PD   with new IP address
assigned.
How - From the host  reservation pick the new subnet/IP address , populate
the lifetimes.* Assign a* *new lease* for this IP address.
Doubt -  Currently we have a lease per client IA_NA/IA_PD. Now we need to
have two leases for the IA_NA/IA_PD.

5. The clients shall stop using the expired IP and  consider using the new
IP's.

Few comments

1. The problem with storing both the old and new configuration - All
replies shall contain multiple addresses per IA_NA even after the client
has stopped using it. I am not sure if this could cause any problem at the
client side. How does the client select when two addresses are assigned.
Or the operator might "flush out" the old config after the renumbering is
complete ?

2.  I want to plan test cases soon for the feature. I understand how test
cases are written in forge. Is there any other source where we need to
integrate our tests ?


Regards
Mayya
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