[j-nsp] MX104 Limitations

[Colton Conor]

We are considering upgrading to a Juniper MX104, but another vendor (not
Juniper) pointed out the following limitations about the MX104 in their
comparison. I am wondering how much of it is actually true about the MX104?
And if true, is it really that big of a deal?:

1.       No fabric redundancy due to fabric-less design. There is no switch
fabric on the MX104, but there is on the rest of the MX series. Not sure if
this is a bad or good thing?

2.       The Chassis fixed ports are not on an FRU.  If a fixed port fails,
or if data path fails, entire chassis requires replacement.

3.       There is no mention of software support for MACSec on the MX104,
it appears to be a hardware capability only at this point in time with
software support potentially coming at a later time.

4.       No IX chipsets for the 10G uplinks (i.e. no packet
pre-classification, the IX chip is responsible for this function as well as
GE to 10GE i/f adaptation)

5.       QX Complex supports HQoS on MICs only, not on the integrated 4
10GE ports on the PMC. I.e. no HQoS support on the 10GE uplinks

6.       Total amount of traffic that can be handled via HQoS is restricted
to 24Gbps. Not all traffic flows can be shaped/policed via HQoS due to a
throughput restriction between the MQ and the QX. Note that the MQ can
still however perform basic port based policing/shaping on any flows. HQoS
support on the 4 installed MICs can only be enabled via a separate license.
Total of 128k queues on the chassis

7.       1588 TC is not supported across the chassis as the current set of
MICs do not support edge time stamping.  Edge timestamping is only
supported on the integrated 10G ports.  MX104 does not presently list 1588
TC as being supported.

8.       BFD can be supported natively in the TRIO chipset.  On the MX104,
it is not supported in hardware today.  BFD is run from the single core
P2020 MPC.

9.       TRIO based cards do not presently support PBB; thus it is
presently not supported on the MX104. PBB is only supported on older EZChip
based MX hardware.  Juniper still needs a business case to push this forward

10.   MX104 operating temperature: -40 to 65C, but MX5, MX10, MX40, MX80
and MX80-48T are all 0-40C all are TRIO based. Seems odd that the MX104
would support a different temperature range. There are only 3 temperature
hardened MICs for this chassis on the datasheet: (1) 16 x T1/E1 with CE,
(2) 4 x chOC3/STM1 & 1 x chOC12/STM4 with CE, (3) 20 x 10/100/1000 Base-T.

11.   Air-flow side-to-side; there is no option for front-to-back cooling
with this chassis.

12.   Routing Engine and MPC lack a built-in Ethernet sync port.  If the
chassis is deployed without any GE ports, getting SyncE or 1588 out of the
chassis via an Ethernet port will be a problem.  SR-a4/-a8 have a built-in
sync connector on the CPM to serve this purpose explicitly.