Black Box LRU4240 Link-based Testing for Public Packet Networks, Delay Monitoring for TCP/IP

Dual Trunk E1 Router

Link-based Testing for Public Packet Networks

The link-based testing feature qualifies and tests PPP-based networks non-intrusively. Using the ICMP ping packet, the unit adds pattern generation and packet sequencing that allows single-ended and collaborative testing. This lets the user test his network from one end to the other using any TCP/IP-based test equipment. Link-based testing encapsulates a BERT pattern inside an ICMP message that the remote Dual Trunk E1 Router reflects. The packet can then be directed to test the network, or LAN port. Patterns supported include 511, 1023, 2047, all 1s, all 0s, and alternating 1s and 0s.

Delay Monitoring for TCP/IP

The delay monitoring feature provides network delay measurement beyond the link between the Dual Trunk E1 Router and any IP-addressable device on the network. Blackbox measures delay by using ping packets, which timestamp and obtain round-trip delays to specific IP addresses. The traffic added to support the measurement is minimal, and the user can configure the frequency. The length of the ping packet can allow delay measurements at different frame sizes. A user who is concerned about bandwidth taken away by the measurement can configure the test for a single, short ping every few minutes, making the test bandwidth penalty virtually non-existent.

The link-based testing and delay monitoring features allow network managers to test links and quantify delays, and are especially useful during network installation and trouble isolation. Both features provide the benefit of circuit-level testing across the network.

Non-Disruptive Testing

The Link Layer Diagnostics and Delay Monitoring are non-disruptive to normal traffic. Unlike hard loopback tests that affect the line, Link Layer Diagnostics do not take the line out of service.

Depending on the link speed and the test specified, Link Layer Diagnostics uses some of the bandwidth that would otherwise be available for payload. This bandwidth reduction is negligible if the test is specified with short and infrequent packets.

On point-to-point networks Link Layer Diagnostics do not disrupt payload traffic.

Menu-9B—Link Layer Diagnostics

Link Layer Diagnostics uses an encapsulated Bit Error Rate Test (BERT) pattern inside ping messages and reflects the BERT pattern from the remote unit.

1.Select a pattern test.

2.Select the IP address of the equipment to send the PING message. Select the local or remote router, or the remote Dual Trunk E1 Router.

3.Select a port to test.

Ports are NET, Ethernet, and COM.

4.Select the Test Interval

Select time in seconds between 2 ping messages.

72 SALES: 0870 90 10 750 Dual Trunk E1 Router User’s Guide