Cisco Cisco 2800 3800 Series 1-Port (SFP) Gigabit Ethernet High-Speed WIC

Antenna Guide for ISR and CGR with Verizon Wireless 4G LTE

Choosing more appropriate antennas: This option can help overcome issues such as weak signal due to distance

from LTE cell towers, signal loss or noise due to physical location, or signal obstruction. The challenge is the

availability of various antennas to test with, as these are optional and purchased separately. When there are issues

obtaining “good” LTE signal, and placement of the existing dipole antennas does not resolve it, a site survey from a

service provider is recommended. If this is not feasible, the following guidance may assist in determining the

appropriate antennas to acquire. Again, a site survey from a provider who can bring various antennas is best.

The included dipole antennas are sufficient for most locations. Placement near a window, on upper floors

may assist with signal reception. The thin low-loss extension cables with Cisco SKUs may be needed.

Where an indoor antenna cannot be placed near a window, using an indoor ceiling mount antenna in an open

area may assist in achieving better signal. Low-loss extension cables with Cisco SKUs may be needed.

If there is no location within the building where “good” signal can be obtained. External antennas can be

used. Use of external antennas greatly reduces physical obstruction, allowing a stronger signal received. If

there are multiple cell towers nearby and the signal is weak, an omnidirectional antenna with higher gain can

be used. If there is only 1 cell tower nearby and the signal is weak, a directional antenna can be used.

Outdoor LTE antennas and cables available for CGR 2010 function with ISR LTE eHWIC/819.

All Cisco LTE antennas and cable also operate with 3G and 2G

Resolving fallback from 4G to 3G: Locations may experience fallback from 4G LTE to 3G EVDO. This can be caused

by the LTE signal being below a certain level (even for a moment), and the EVDO signal being above a certain level.

The radio access technology (RAT) chosen by an LTE device is based on 3GPP specification and the radio signal

reception of the device's LTE modem. The RAT value can be seen from the ISR "

show cell x radio

" enable-mode

command. LTE 3G-to-4G reselection requires the connection to be dormant for 7-10 seconds in the Verizon LTE

network. For a mobile phone, return to LTE is feasible. For a router with multiple devices behind it, the user traffic,

keep-alives, and normal protocol messages may keep a dormancy period from occurring for hours or days. Another

factor is that even a transient condition can cause the LTE modem to choose 3G. Below are 3 mitigation options:

Confirm that the ISR is at a stationary location and has consistently acceptable LTE signal. Lock the

connection to LTE (IOS enable-mode command "

cellular x lte tech lte

"). The I modem will only connect to

LTE. If there's no LTE signal, no connection will be made. This setting is permanent until overridden.

Manually check RAT. If on 3G, power off/on the modem's radio. This will cause a brief disconnect (IOS

config: "controller cell x", "lte radio off", "no lte radio off").

Use the available auto 4G check/reset app available here:

https://supportforums.cisco.com/document/12620516/restore-lte-service

Information on Cisco LTE antennas as cables can be found at these locations:

www.cisco.com/en/US/docs/routers/access/interfaces/ic/hardware/installation/guide/EHWIC-4G-LTEHW.html

LTE installation guide for ISR

www.cisco.com/c/en/us/td/docs/routers/connectedgrid/antennas/installing/cg_antenna_install_guide/Overview.html

CGR antenna installation guide

www.cisco.com/c/en/us/td/docs/routers/access/interfaces/NIM/hardware/installation/guide/4GLTENIM_HIG.html#61402

ISR 4K LTE NIM installation guide