Link Aggregation - D-Link DES-3250TG User Manual

RSTP is capable of more rapid transition to a forwarding state – it no longer relies on timer
configurations – RSTP-compliant bridges are sensitive to feedback from other RSTP-compliant bridge
links. Ports do not need to wait for the topology to stabilize before transitioning to a forwarding state. In
order to allow this rapid transition, the protocol introduces two new variables: the edge port and the
point-to-point (P2P) port.
Edge Port
The edge port is a configurable designation used for a port that is directly connected to a segment where
a loop cannot be created. An example would be a port connected directly to a single workstation. Ports
that are designated as edge ports, transition to a forwarding state immediately without going through
the listening and learning states. An edge port loses its status if it receives a BPDU packet, immediately
becoming a normal spanning tree port.
P2P Port
A P2P port is also capable of rapid transition. P2P ports may be used to connect to other bridges. Under
RSTP, all ports operating in full-duplex mode are considered to be P2P ports, unless manually
overridden through configuration.
802.1d/802.1w Compatibility
RSTP can interoperate with legacy equipment and is capable of automatically adjusting BPDU packets
to 802.1d format when necessary. However, any segment using 802.1 STP will not benefit from the
rapid transition and rapid topology change detection of RSTP. The protocol also provides for a variable
used for migration in the event that legacy equipment on a segment is updated to use RSTP.

Link Aggregation

Link aggregation is used to combine a number of ports together to make a single high-bandwidth data
pipeline. The participating parts are called members of a link aggregation group, with one port
D-Link DES-3250TG Standalone Layer 2 Switch
802.1d STP 802.1w RSTP
Disabled Discarding
Blocking Discarding
Listening Discarding
Learning Learning
Forwarding Forwarding
Table 5- 1. Comparing Port States
Forwarding
No
No
No
No
Yes
17
Learning
No
No
No
Yes
Yes