UDP (Layer 4) Testing
PacketExpert™ provides independent Ethernet/VLAN/MPLS/IP/UDP testing at wire speed for applications such as BERT, RFC 2544, and Loopback, also supports optional applications for advanced testing such as Record and Playback, ExpertSAM™, PacketBroker, Multi Stream UDP/TCP Traffic Generator and Analyzer, and ExpertTCP.
Transport Layer (Layer 4) provides end-to-end, error-free reliable data transfer. TCP and UDP are the most common Layer 4 protocols. For Layer 4 testing, source and destination UDP ports need to be configured in addition to MAC and IP addresses.
Two test scenarios at Layer 4 are as depicted in the diagram where the information in layer 4 is transmitted through the network in packets.
The test setup for Layer 4 is similar to test setup for Layer 3, as UDP is carried over IP. At Layer 4, proper UDP packets are sent (instead of raw IP packets as in the case of Layer 3 testing). The testing at Layer 4 (UDP) is useful in cases where there are firewalls in the network, which typically intervene at network boundaries and handle/modify packets at Layer 4 (TCP/UDP).
Scenario 1 - Source & Destination PC are located within the same IP network, and hence are directly reachable
Indirect Routing Test Setup at Layer 3/4 within the same IP network
Scenario 2 - Source & Destination PC are located at different IP networks, and are connected through routers
Indirect Routing Test Setup at Layer 3/4 between different IP networks
Layer4 configuration requires source and destination UDP ports to be defined. User can choose to allow hardware to calculate/verify checksum or provide a fixed value.