Bandwidth CAC Fallback Based on ICMP Failure

For networks where backup links (operating in active-standby mode) from CE-routers to the MPLS backbone are provisioned with less bandwidth than the primary links, the Oracle® Enterprise Session Border Controller can:

• Detect remote link failures
• Trigger bandwidth updates at the realm level when using backup links
• Detect remote link failback to primary

To do so, the Oracle® Enterprise Session Border Controller monitors the primary link status using ICMP echo requests (or pings). It issues the pings at regular intervals, forming a heartbeat mechanism. The CE-router can respond to these pings on the primary link, which is represented by the WAN IP address. When this link fails over, the backup link assumes the same WAN IP address but is not responsive to the pings. This way, the Oracle® Enterprise Session Border Controller determines failover when the ICMP ping fails.

When there is an ICMP ping failure, the Oracle® Enterprise Session Border Controller adjusts the realm’s available bandwidth pool from its maximum bandwidth setting to its fallback setting. If the fallback amount is less than the maximum amount, it is possible for the Oracle® Enterprise Session Border Controller to start rejecting calls. It does so until enough calls are released to free adequate bandwidth to stay under the fallback limit and still accept calls.