SBO analyses voice and data packets over your network and strips out anything that is not essential, only data essential to the delivery of voice data. SBO also gives voice data precedence over other types of data ensuring that call quality is always maintained in real-time.
1: Removes inefficiencies of VoIP
SBO uses G.729 @ 10mS compression which only uses 8.23Kbit/s of available bandwidth, regardless of the type of WAN it is running over. Compare this to a typical VoIP call over ADSL which uses 84.4kbit/s, in fact SBO reduces overheads per call to less than one byte per packet.
How does SBO benefit the end user?
What this means for the end user running SBO is that many more calls can be sent on their current link without any compromise in quality. Or users can keep sending their current volume of calls over lower bandwidth. In both instances the end user saves money by reducing bandwidth requirements.
2: Implements “byte level” QoS
With SBO Quality of Service (QoS) is implemented at both ends of link meaning that voice and data are controlled going in both directions. Data packets are sliced with zero overhead while voice packets are not forced to wait (causing jitter and delay in the call quality).
Data Packets Take Priority without SBO
Voice Packets Take Priority with SBO
SBO does not reduce the Data MTU over a link and allows for 100% of the available bandwidth to be used. Because SBO works well over slow links, it is possible to use a 128Kb link to send both voice and data without any compromise on quality.
3: Implements call access control
Existing calls are protected with SBO, it is impossible to over-subscribe a link. Worst case scenario is that a new call will just get dead air (call will not be able to be made). With IP-PBX busy tone will be returned
SIP call rejection
Once a link has reached its call limit SIP “INVITE” messages are intercepted by SBO. A reply message is configurable.
4: Can bond links together in an active-active mode
SBO can be set to use an additional link in either an active or passive mode. In active mode SBO efficiently bonds links of different speed together, reducing latency for larger packets.
Redundant Array of Inexpensive Networks or (RAIN) is the term we have given SBO’s multiple link resiliency. When multiple links are bonded SBO sends synchronous data across both links in an “active-active” mode. What this means is that when a link fails it is removed in under a second resulting in no calls being dropped (no failover delay). Importantly RAIN mode works with two or more links and also supports links form different suppliers (eg. ADSL supplied from different ISPs).
Passive mode leaves the additional link idle until it is required. Ideally passive mode is used with ISDN or 3G backup. Passive links can be automatically tested for availability. Switching links in passive mode takes around a second plus any establishment delay on the link.
5: Real-time Monitoring
SBO provides real-time monitoring of underlying link quality and its effect on voice. Packet loss, latency and jitter are also monitored. SBO’s monitoring is not affected by link loading and any faults with the link (ADSL down for example) can be distinguished from customer created ones.
Simple Network Management Protocol (SNMP)
SBO supports SNMP giving your administrators detailed information including: calls in progress and general system health.
6: Deploying SBO
SBO is a tunnel technology and needs a SBO enabled device at the end of each link. When talking about a “link” in regards to SBO we mean a single WAN link, back to back WANs, or even “the Internet”.
SBO can be deployed in either a point-to-point configuration or a service provider/enterprise configuration.
Typical Service Provider / Enterprise Configuration
For deployments with a high number of geographical sites SBO can be installed in a Central Server configuration (usually in a Hosting Environment) with satellite sites each having a smaller SBO enabled device installed on the end of the connecting link. SBO can be setup in N+1 configuration at the core of any enterprise/service provider.