Maximum One-Way Delay between Cisco Unified Communications Manager Servers: CCIE Collaboration 400-051 Exam - Cisco

Maximum One-Way Delay between Cisco Unified Communications Manager Servers

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What is the maximum one-way delay, in milliseconds, between any two Cisco Unified Communications Manager servers in a non-Session Management Edition cluster over an IP WAN?



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A. B. C. D. E.


The maximum one-way delay between any two Unified CM servers should not exceed 40 msec, or 80 msec round-trip time.

Propagation delay between two sites introduces 6 microseconds per kilometer without any other network delays being considered.

This equates to a theoretical maximum distance of approximately 3000 km for 20 ms delay or approximately 1860 miles.

These distances are provided only as relative guidelines and in reality will be shorter due to other delay incurred within the network.

In a Cisco Unified Communications Manager (CUCM) cluster, one-way delay refers to the time taken for a packet to travel from one CUCM server to another over the IP WAN. This delay can have an impact on the performance and quality of voice and video communications between devices registered to these CUCM servers.

The maximum one-way delay that is acceptable in a non-Session Management Edition (non-SME) CUCM cluster over an IP WAN is dependent on the CUCM version and the type of traffic being transmitted. However, in general, Cisco recommends that the one-way delay should not exceed 80 milliseconds for voice traffic and 150 milliseconds for video traffic.

Based on this recommendation, we can eliminate options A, B, and E, as they all have maximum delays lower than the recommended 80 milliseconds.

Option C, with a maximum one-way delay of 80 milliseconds, is the most likely correct answer, as it meets the recommended delay for voice traffic.

Option D, with a maximum one-way delay of 160 milliseconds, exceeds the recommended delay for voice traffic but may be acceptable for certain types of traffic, such as video or data.

It is important to note that the recommended maximum one-way delay for CUCM clusters may vary depending on the specific deployment scenario and network conditions. It is always recommended to consult the relevant Cisco documentation and perform proper testing to determine the optimal delay for a particular deployment.