CCNA Voice Summary – Part 11

Quality of Service Disadvantages of packet switched networks can be solved using QoS. ITU recommendations (G.114 specifications): Delay < or = 150 ms one way Jitter < or = 30 ms Packet loss < or = 1% Bandwidth for Voice and Video RTP is subject to codec, sampling, L2 and L3 overhead. Bandwidth for signaling … Continue reading CCNA Voice Summary – Part 11 →

CCNA Voice Summary – Part 8

CUCM (Cisco Unified Communication Manager / Call Manager) Fully featured Voice and Video. Supports up to 30000 IP phones per cluster in reality around 20000. A cluster is a shared database. Multi-server redundancy. Multi-site support. Very expensive compared to the rest. It runs on a hardened red hat Enterprise Linux platform as an appliance with … Continue reading CCNA Voice Summary – Part 8 →

CCNA Voice Summary – Part 7

Cisco CME (Cisco Unified Communication Express/ Call Manager Express) Designed for enterprise branch offices and small medium businesses. It runs on a router. Supports a max of 450 IP phones but realistically 100 phones. You can get voicemail using Unity Express (CUE) AIM card and the Network Module NM card. AIM - flash memory and … Continue reading CCNA Voice Summary – Part 7 →

CCNA Voice Summary – Part 5

; Voice over IP VOIP process: Sample analog Voice or Video ->; Encode to digital value ->; transmission in an IP data payload Uses Signaling Protocol for setup and control of the call and a Media Protocol for the payload. They are transmitted separately. Signaling is typically sent using TCP (connection oriented) because it is … Continue reading CCNA Voice Summary – Part 5 →

CCNA Voice Summary – Part 4

Circuit Switched Network Involves 2 nodes that establish a dedicated circuit in order to communicate. The channel remains up during the whole conversation. PSTN is the largest Circuit switched network in the world. The PSTN uses SS7 signaling. Advantages: Dedicated Channel; Excellent quality; delay and bit rate is constant Disadvantages: Not always enough available channels; … Continue reading CCNA Voice Summary – Part 4 →