NT10G05 USER MANUAL
76-02-105 Rev.B
Page 70 of 80
4.2.3.3.1.2 Frame Size
The Y.1564 test mode supports either single packet size tests, or can support an
Ethernet mix (emix) of up to 5 packet sizes which are sent in a repeating sequence
To allow for testing frames above 1518 bytes the packet sizes to test are
configurable, and the letter shorthand may be used as follows:
a
64 bytes
b
128 bytes
c
256 bytes
d
512 bytes
e
1024 bytes
f
1280 bytes
g
1518 bytes
u
User defined
h
MTU, as defined in the SLA
The packet size range for the test should be 1 or more size, or letter.
4.2.3.3.1.3 User Defined Size
To support testing at sizes in excess of 1518 bytes, or to support particular sized
packets a user defined packet is available where the size may be defined in the
range:
64 to 10240 bytes
Note, that the packet size excludes tags.
4.2.3.3.1.4 Training Period
Whilst some services are provided as true L2 single broadcast domain networks,
most are actually provided as VPLS tunnels over MPLS core networks. When a
packet reaches the edge of such networks forwarding tables need to be configured
in order to forward the packets. Due to this connection initialisation it is possible to
see some packet loss at the beginning of a test.
However, to get around this issue a training period may be introduced before the test
is run for real. During the training period, low rate packets are transmitted to the
required loopback device without being monitored. This allows all forwarding tables
etc. to be set up such that the test will run from the first packet without loss.
