User's Manual

Exalt Installation and Management Guide
EX-r Series GigE Digital Microwave Radios
201872-003 16
2015-10-23
failures. This provides redundancy for catastrophic failure of the SYNC SOURCE and maintains GPS
synchronization. If the GPS source is lost (for example, due to failure of the GPS unit, a disconnected
cable, or satellite blockage), the AUTO SYNC radio resumes synchronization duties for all collocated
radios.
Virtual Local Area Network (VLAN)
VLAN segments information in a single connection and creates multiple separate connections to
secure information of one type or for one set of users from other information types or for other sets of
users. Exalt’s VLAN communications implementation adheres to the IEEE standard 802.1q.
In most cases, an Exalt radio acting as a Layer 2 bridge between two locations is only required to pass
traffic with VLAN tagging. Without additional configuration, all Exalt radios support frame sizes in
excess of 1900 bytes, which currently supports all defined VLAN packet sizes.
Some situations require Exalt radios to act upon VLAN traffic and perform any or all of the following
functions:
• Connect specific traffic, using VLAN tagging, to different purposes, such as management traffic to
the radio’s NMS system.
• Allow only traffic with specifically assigned VLANs to pass across the link, blocking all other
VLANs or any non-VLAN traffic.
• Allow management access only through a VLAN connection, leaving the main traffic transparent.
Link Symmetry
The default configuration of EX-r Series GigE radios provides 50/50 symmetrical throughput. The Tx/
Rx Throughput Ratio setting enables programming different symmetry for applications where
significantly higher throughput in one direction is anticipated such as for video broadcast, video
aggregation, or remote server/storage WANs.
Exalt does not recommend placing two links with asymmetry back-to-back in a serial configuration
due to the TDD cycle of the radios. This configuration requires that one radio transmits in an
overlapping time period while another radio is receiving. Physical antenna isolation and/or frequency
channel spacing may accommodate this configuration. Asymmetry is, however, ideal for single-hop,
multi-link hub/spoke architectures, or simply single independent links.
TDD frame sizes of 2ms and 5ms are supported. The 5ms configuration maximizes the aggregate
throughput of the radio for every situation. The 2ms configuration reduces latency to meet latency-
critical applications, especially for multi-link and TDM circuit support. The following RF BW/mode
combinations are supported for these two configurations:
• 16MHz/Mode1
• 16MHz/Mode2
Note: If an application only requires the transparent passing of VLAN traffic, disable the VLAN
function.
Note: Asymmetry is only supported for a specific subset of system configurations that are
optimized for typical asymmetric applications.
Asymmetry is not currently supported in all EX-r Series GigE radio models. Consult your
Exalt representative for details.