Cisco Cisco 1800 2800 3800 Series 4-Port Serial High-Speed WIC
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Technology or Service
Uplink
Downlink
Average Latency (Round-Trip Time [RTT])
EVDO Rev A
500 kbps
800 kbps
100 ms
LTE (AT&T)
2-5 Mbps
5-12 Mbps
40 ms
LTE (Verizon)
2-5 Mbps
5-12 Mbps
40 ms
Note: AT&T 4G LTE and Verizon 4G LTE provide similar throughput.
2.4 Shared Access
A cellular network is a wireless access network wherein the available radio spectrum is shared between multiple
user devices that connect to the same cell tower at any given time. The available theoretical maximum bandwidth
is shared among the active users who request access to the network. As a result, it is difficult to predict precisely
the available bandwidth to any particular user in a given cell.
2.5 Radio Signal
Receive Signal Strength Indicator (RSSI) is a circuit to measure the strength of an incoming signal. The basic
circuit is designed to pick RF signals and generate an output equivalent to the signal strength. The ability of the
receiver to pick the weakest of signals is referred to as receiver sensitivity. When the receiver sensitivity is high,
the performance is better. Circuits measure the signal strength based on the output voltage. If the signal strength is
good, the output voltage is higher. If the signal strength is low, the output voltage is poor.
These performance characteristics mean that the sweet spot for the 4G HWIC is basic real-time, 5-10 Mbps
applications. As networks evolve, latencies decrease, quality of service (QoS) becomes available, and real-time
applications (such as high-definition video calls) become viable.
2.6 QoS over 4G LTE Connection
Cisco IOS QoS mechanisms are applicable on EHWIC 4G LTE interfaces. RAN QoS is not yet available on
production cellular networks. Therefore, though the traditional IP QoS is available on the ISRs and on the 4G
EHWIC interface, mapping to the airlink is not available. Nonetheless, you can use the Cisco IOS QoS capabilities
to improve the application experience. Techniques such as congestion management, congestion avoidance,
policing and shaping, and Modular QoS CLI (MQC) are beneficial.