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High-Performance Switch/Routers
Published in James Aweya, Designing Switch/Routers, 2023
LLDP is a Link Layer protocol (specified in IEEE 802.1AB) that is used by network devices to advertise their identities, capabilities, and neighbors on Ethernet LANs. The information gathered with LLDP can be stored in a network device’s MIB and queried using SNMP. By examining the hosts in an LLDP-enabled network and querying their MIBs, the topology of the network can be discovered (Figure 2.27). The information that may be retrieved from the device MIBs include system name and description, device port name and description, VLAN ID and name, IP management address, system capabilities (Layer 2 forwarding, Layer 3 forwarding, etc.), MAC and PHY information, Power-over-Ethernet (PoE) Medium Dependent Interface (MDI) power, IEEE 802.3ad Link Aggregation.
Virtualised Environment for Learning SDN-based Networking
Published in IETE Journal of Education, 2020
Oscar Polanco, Fabio G. Guerrero
By default, OpenFlow Manager installed 17 flow entries in table 0 of the two OpenvSwitch switches. The first entry, programmes the switches to forward LLDP (Link Layer Discovery Protocol) traffic into the controller, which allows the controller to automatically learn about the topology of the SDN network and get information about connected devices. The next 15 entries (line 34 in Table 2 shows one of these, with a priority of 2) instruct the switches so that for each input port (there are 15 ports), the traffic must be forwarded concurrently to the other output ports and to the controller. First, this allows the switches to broadcast the traffic that does not have a match on entries whose priority is greater than 2 as a last resort. Second, it enables the controller to learn about such traffic to programme the switches with more specific flow entries, such as the flow entry listed in line 37. The entry in line 35, which has a priority of 0 (the lowest priority), instructs the switches to discard the traffic that does not have a match on entries whose priority is greater than 0.