Skip to main content

6.6.1. Clock Sweep

6.6.1. Clock Sweep​

The clock sweep approach uses planning in advance and the use of count-down TTLs to time out mappings that have already been cached. The default setting for an EID-to-RLOC mapping TTL is 24 hours. So, there is a 24-hour window to time out old mappings. The following clock sweep procedure is used:

  1. 24 hours before a mapping change is to take effect, a network administrator configures the ETRs at a site to start the clock sweep window.

  2. During the clock sweep window, ETRs continue to send Map-Reply messages with the current (unchanged) mapping records. The TTL for these mappings is set to 1 hour.

  3. 24 hours later, all previous cache entries will have timed out, and any active cache entries will time out within 1 hour. During this 1-hour window, the ETRs continue to send Map-Reply messages with the current (unchanged) mapping records with the TTL set to 1 minute.

  4. At the end of the 1-hour window, the ETRs will send Map-Reply messages with the new (changed) mapping records. So, any active caches can get the new mapping contents right away if not cached, or in 1 minute if they had the mapping cached. The new mappings are cached with a TTL equal to the TTL in the Map-Reply.

Last updated on