4-60 MAX 6000/3000 Network Configuration Guide
Configuring Individual WAN Connections
Configuring MP, MP+ and BACP connections
Take into account that you do not know ahead of time how many bundles span the stack, or
how many multi- or single-channel calls you are going to get. You can base an estimate on
your traffic expectations. But in most situations, the majority of bundles are on a single unit,
for which there is no overhead.
Suggested LAN configurations
Total Ethernet usage is approximately 5116Kbps for a MAX stack handling 82 single-chan nel
calls, 41 two-channel stacked calls, and 41 two-channel nonstacked calls. Because Ethernet
capacity generally does not achieve more than 50% utilization, this configuration uses up the
available Ethernet bandwidth.
The total number of channels in this configuration is 246. Therefore, a stack of three MAX
units, each having three T1 lines with this usage profile, uses all of the Ethernet bandwidth.
The basic limitation from the above examples is the speed of the LAN. One way to increase the
speed of your LAN is to attach each unit to a separate port of a 10/100 Ethernet switch, and
then use a 100Mbps connection to the backbone LAN. This configuration enables each unit to
use up to a full 10Mbps of Ethernet bandwidth, and the entire stack combined can generate up
to a full 100Mbps of Ethernet data. Once again assuming that the 100Mbps is saturated at 50%
usage, you can use up to 51200Kbps of bandwidth, or 10 times more than in the preceding
example. The mixed environment of single-channel and two-channel calls now results in a
maximum of 2460 channels or 102 T1 lines, or no more than 34 MAX units in a stack. Note
that the success of this strategy depends on limiting stacked channels per MAX unit to the n/3
limit mentioned above.
Suggested hunt group configurations
Whenever you stack MAX units, it is important to limit the number of multichannel calls that
are split between them. The following suggested configurations reduce the overhead for a
multichannel call by keeping as many channels as possible on the same unit.
MP+ and MP-with-BACP calls
Figure 4-7 shows the suggested hunt group setup for a typical MAX stack that receives only
PPP, MP+, or MP-with-BACP calls. Each MAX unit has three T1 lines. All the T1 lines in a
MAX unit share a common telephone number and they are in a hunt group that does not span
MAX units. The illustration shows these three local hunt groups with telephone numbers
555-1212, 555-1213, and 555-1214. In addition, a global hunt group, 555-1215, spans all the
T1s of all the MAX units in the stack.
Users that access the MAX unit dial 555-1215, the global hunt group number. The telephone
company sets up the global hunt group to distribute incoming calls equally among the MAX
units. Namely, the first call dialing 555-1215 goes to MAX #1, the second call to MAX #2, and
so on. If you use this configuration, you must configure each of the MAX unit’s Line N
profiles with the local hunt group numbers. For example, for MAX #1 in Figure4-7, you
would set the Ch N # parameters to 12 (the last two digits of the 555-12 12 hunt group number).
You can achieve the same distribution without a global hunt group by having one third of the
users dial 555-1212, one third di al 555-1213, and one third dial 555-1214. You can leave the
Ch N # parameters at their default setting (null) if you do not have a global hunt group.