It also provides a mechanism for rapid
detection of topology changes, and a mechanism to convey additional node information
to the other nodes on the ring.
No Control of Delay and Delay Variation from Switch to Switch
Mechanisms that control delay and delay variation are crucial for networks that deliver
IPTV and voice services. In a network of 3 or more switches, connected serially, there
is no provision within the 802.3 MAC to ensure packets on the network are delivered.
Ethernet LANs require retransmission of dropped or lost packets or induce significant
delay due to queuing. However, carrier networks cannot maintain SLAs or quality of
user experience for consumers of IPTV or voice services if they encounter significant
amount of lost packets or packet delay and variation.
No Fairness Control Mechanism
The 802.3 MAC has no signaling mechanism among devices to communicate the congestion
state of other switches on the network. This lack of visibility often leads to
unexpected congestion on individual links. In addition, due to head of line blocking customers
that are closest to their destination, a Central Office for instance, will receive
better service than those that are farther away.
Pages:
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806