How to Free Up Memory on a Cisco Catalyst 4948

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Call Forward And Call Hunt on CUCM

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Call forwarding is one of the features of the call coverage in Cisco CUCM. Call Hunting is when CUCM distributes a call on more than one Directory Number (DN), whether consecutively or simultaneously, depending on the algorithm. Hunt Pilot A Hunt Pilot is the entry point for the whole call hunting process. It is hit by a Call. The Hunt Pilot number is a dialable entity and has many similarities with Route Patterns : We can configure Route Filters with Hunt Pilots, Hunt Pilots can Provide Outside Dial Tone , We can set Hunt Pilots with the Urgent Priority flag, They can route or block calls, They can apply Calling and Called Party Transformations. Hunt Lists After hitting the Hunt Pilot, the call is presented by CUCM to the Hunt List. Each Hunt List contains one or more ordered Line Groups. A Hunt List can be pointed by one or more Hunt Pilots. Line Groups Each Line Group contains one or more member (we’ll refer to them as Hunt members, hunt parties or Line Group members). A Line Grou...
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DNS Name Compression

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In this article I explain how the DNS name compression works and I give an example. DNS name compression A DNS response message can contain the same domain name multiple times. This repetition is a waste of bits in the message. A compression technique can be used to reduce the number used bits and replace the repeated domain name by a pointer. A compression label is a pointer that appears in the packet instead of the count byte and the following label items. It is written on 16 bits and has the following format: Figure: the DNS Offset field © IBM.com Remember when I said that the label length of a data label is one byte long, and its value is between 0 and 63? 63 is 00111111 in binary. The pointer, however, has the first two bits set to 1, to differentiate it from data labels. Here is how the pointer is structured : the first 2 bits are set to 1, the 14 remaining bits describe the offset, i.e. the position of the compression target from the beginning of the DNS message. The pointer can...
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Throughput, Goodput And Latency

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To define Throughput, Goodput and Latency, we need to understand some terms first such as the propagation delay, the packetization delay, the queueing delay, etc. Propagation Delay The propagation delay can be calculated with the following formula: Propagation delay = distance / speed of the signal where “distance” is the length of the media The propagation delay can be expressed in terms of RTT of a packet. On a point to point link, when we transmit a series of packets from point A to point B: the propagation delay of all the packets equals the propagation delay of a single packet. This is important to know when we will later calculate the end-to-end delay. Transmission time (Packetization delay) Transmission time is the time elapsed from the first bit put on the link till the last bit is put on the link. Transmission time is also known as Transmission Delay or Packetization Delay in packet switching networks. Why did I say packetization delay in packet switching networks? Because i...
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