Service Activation Testing
Today's Ethernet WAN services support multiple applications, some of which may be sensitive not only to service bandwidth but to other criteria, including circuit delay and delay-variation for example. Service Providers are increasingly required to demonstrate to their customers that, at the time of hand-over, newly provisioned circuits are operating in accordance with agreed performance criteria detailed within their Service Level Agreement (SLA).
Consequently, Service Providers use tools embedded within Advanced Ethernet Demarcation Devices to generate test traffic at one end of a circuit, loop this back at the other end, and generate comprehensive reports regarding key performance criteria across the link, to demonstrate compliance with the terms of the Service Level Agreement (SLA).
Our MetroCONNECT family of EDDs all support the two widely accepted test reporting procedures for Ethernet networks, namely RFC 2544 and ITU-T Y.1564, using either Layer-2 (Ethernet MAC-Addressed) test traffic, or Layer-3 (IP-Addressed) test traffic. In either case traffic generated in the EDD at one end of an link is reflected back from that at the other, using Source Address/Destination Address swapping at line rate, in order not to provide invalid addressing within the network.
RFC 2544 for Service Activation Testing
RFC2544 is arguably most appropriate for situations in which the boundaries of network performance are unknown, or for which no clear Service Level Agreement (SLA) has already been defined. The test typically involves the transmission of packets in a pre-determined sequence of sizes, perhaps from the Ethernet minimum of 64 bytes (excluding overheads due to VLAN tagging etc.) in steps up to the maximum packet size supported across the Service Providers equipment, or likely to be used by the customer. The test will attempt to flood the network at maximum line rate, and if errors are detected, for instance by a level of packet loss due to the WAN not supporting the transmitted rate, then the test will follow an algorithm to progressively back-off and then steadily increase traffic flow until the maximum sustainable rate is determined. Once this rate is determined for each of the range of packet sizes specified within the test, then key metrics are measured and recorded at the maximum rate.
ITU-T Y.1564 for Service Activation Testing
The Y.1564 profile test can be an excellent choice for testing against a pre-defined 'Committed Information Rate' (or 'CIR', typically part of an Service Level Agreement definition). Typically the test sequence involves traffic generation increasing over a minimal number of increments up to the CIR, for a given packet size. Provided that the CIR is met, the test proceeds to record characteristics similar to those of the RFC2544 test. This is repeated for different packet sizes in order to provide a full qualification of the Network service.
Y.1564 is generally the test profile of choice for aggregated network architectures. If the network architecture comprises a central 'HQ' location linked to remote sites, then typically the central site may be served by a 'fat pipe' connection, let's say at 1Gbps, whilst individual remote sites may be served by lower speed connections, perhaps 10Mbps or 100Mbps depending on their size. If testing is conducted from the central site to a remote location across a newly provisioned link, then using an RFC2544 test would be inadvisable. Since RFC2544 is not limited by a defined Service Level Agreement (SLA), but only by the size of the locally available bandwidth, such a test would initially attempt communication to the new site at the full 1Gbps available centrally, thus effectively blocking all other communications to existing sites during the course of the test. in contrast, a Y.1564 test can be limited specifically to the bandwidth of the actual link under test, so will not jeopardise the existing production network serving other sites.
Example: Network 'Circuit Activation Testing'
'Y.1564' circuit activation testing can be conducted to any remote branch location, independently of other links which may be running live data. Testing verifies that 'Committed Information Rate' is being achieved and reports Latency, Jitter and potentially Packet-loss Ratio for the new link, whilst regular traffic to other sites is running through the HQ link.
'RFC2544' profile testing could alternatively be used for individual Pt-to-Pt. links
Operatives at the NOC can remote log-in to the units to:
- Configure and setup
- Initialise tests
- Monitor Test Progress
- View test reports
Network Performance, management and provisioning
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