Hi all;
Please read the following statement:
Our MCLT is set to 5 minutes. When DHCP1 is approached by Client 1 to lease it an address, instead of leasing an address for 8 days it leases an address to Client 1 for 5 minutes. DHCP1 then informs DHCP2 that Client 1 has leased an address. DHCP2 can add the details of Client 1 to its DHCP database, but crucially marks the lease as 8 days. After 5 minutes, Client 1 contacts DHCP1 again and receives the same address, but this time with an 8-day lease. Both DHCP1 and DHCP2 now know this address is leased to Client 1 for 8 days.
Let's take a look at how MCLT works during a failure of DHCP1. DHCP1 is approached by Client 1 to lease it an address. DHCP1 leases an address for 5 minutes (based on the MCLT), but before DHCP1 can share this information with DCHP2, DHCP1 fails. DHCP1 and DHCP2 had been maintaining a persistent TCP connection with each other over port 647, but now that DHCP1 is no longer there, DHCP2 will transition the scope to Communication Interrupted state.
When Client 1 attempts to contact DHCP1 after 5 minutes (At 50% of MCLT Client1 will send a unicast to DHCP1 trying to renew the lease. DHCP1 will not respond, since it is down. At 87% of MCLT, the Client will do a broadcast to renew its lease.), it will fail and subsequently send out a general message for any DHCP server to respond.This will be registered by DHCP2, which will recognize that Client 1 has an address that was provided by its failed partner using the MCLT. This will cause DHCP2 to lease Client 1 the same address for the full 8 days and add the details to its database even though it hasn't taken over running the entire scope yet.
Now. I want to know that how DHCP2 can understand (based on MCLT) that Client1 has an address that was provided by its failed partner?
Thanks
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