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Juniper MX Series by Harry Reynolds, Douglas Richard Hanks Jr.

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MX2020

The release of this book has been timed with a new product announcement from Juniper. The MX2020 is a new router in the MX Series that’s designed to solve the 10G and 100G high port density needs of Content Service Providers (CSP), Multisystem Operators (MSO), and traditional Service Providers. At a glance, the MX2020 supports 20 line cards, 8 switch fabric boards, and 2 routing engines. The chassis takes up an entire rack and has front-to-back cooling.

Architecture

The MX2020 is a standard backplane-based system, albeit at a large scale. There are two backplanes connected together with centralized switch fabric boards (SFB). The routing engine and control board is a single unit that consumes a single slot, as illustrated in Figure 1-39 on the far left and right.

Illustration of MX2020 architecture

Figure 1-39. Illustration of MX2020 architecture

The FPC numbering is the standard Juniper method of starting at the bottom and moving left to right as you work your way up. The SFBs are named in the same method starting with zero starting on the left and going all the way to seven on the far right. The routing engine and control boards are located in the middle of the chassis on the far left and far right.

Switch Fabric Board

Each backplane has 10 slots that are tied into eight SFBs in the middle of the chassis. Because of the high number of line cards and PFEs the switch fabric must support, a new SFB was created specifically for the MX2020. The SFB is able to support more PFEs and has a much higher throughput compared to the previous SCBs. Recall that the SCB and SCBE presented its chipsets to Junos as a fabric plane and can be seen with the show chassis fabric summary command; the new SFB has multiple chipsets as well, but presents them as an aggregate fabric plane to Junos. In other words, each SFB will appear as a single fabric plane within Junos. Each SFB will be in an Active state by default. Let’s take a look at the installed SFBs first:

dhanks@MX2020> show chassis hardware | match SFB
SFB 0            REV 01   711-032385   ZE5866            Switch Fabric Board
SFB 1            REV 01   711-032385   ZE5853            Switch Fabric Board
SFB 2            REV 01   711-032385   ZB7642            Switch Fabric Board
SFB 3            REV 01   711-032385   ZJ3555            Switch Fabric Board
SFB 4            REV 01   711-032385   ZE5850            Switch Fabric Board
SFB 5            REV 01   711-032385   ZE5870            Switch Fabric Board
SFB 6            REV 04   711-032385   ZV4182            Switch Fabric Board
SFB 7            REV 01   711-032385   ZE5858            Switch Fabric Board

There are eight SFBs installed; now let’s take a look at the switch fabric status:

dhanks@MX2020> show chassis fabric summary
Plane   State    Uptime
 0      Online   1 hour, 25 minutes, 59 seconds
 1      Online   1 hour, 25 minutes, 59 seconds
 2      Online   1 hour, 25 minutes, 59 seconds
 3      Online   1 hour, 25 minutes, 59 seconds
 4      Online   1 hour, 25 minutes, 59 seconds
 5      Online   1 hour, 25 minutes, 59 seconds
 6      Online   1 hour, 25 minutes, 59 seconds
 7      Online   1 hour, 25 minutes, 59 seconds

Depending on which line cards are being used, only a subset of the eight SFBs need to be present in order to provide a line-rate switch fabric, but this is subject to change with line cards.

Power Supply

The power supply on the MX2020 is a bit different than the previous MX models. The MX2020 power system is split into two sections: top and bottom. The bottom power supplies provide power to the lower backplane line cards, lower fan trays, SFBs, and CB-REs. The top power supplies provide power to the upper backplane line cards and fan trays. The MX2020 provides N + 1 power supply redundancy and N + N feed redundancy. There are two major power components that supply power to the MX2020:

Power Supply Module

The Power Supply Modules (PSM) are the actual power supplies that provide power to a given backplane. There are nine PSMs per backplane, but only eight are required to fully power the backplane. Each backplane has 8 + 1 PSM redundancy.

Power Distribution Module

There are two Power Distribution Modules (PDM) per backplane, providing 1 + 1 PDM redundancy for each backplane. Each PDM contains nine PSMs to provide 8 + 1 PSM redundancy for each backplane.

Illustration of MX2020 power supply architecture

Figure 1-40. Illustration of MX2020 power supply architecture

Air Flow

The majority of data centers support hot and cold aisles, which require equipment with front to back cooling to take advantage of the airflow. The MX2020 does support front to back cooling and does so in two parts, as illustrated in Figure 1-42. The bottom inlet plenum supplies cool air from the front of the chassis and the bottom fan trays force the cool air through the bottom line cards; the air is then directed out of the back of the chassis by a diagonal airflow divider in the middle card cage. The same principal applies to the upper section. The middle inlet plenum supplies cool air from the front of the chassis and the upper fan trays push the cool air through the upper card cage; the air is then directed out the back of the chassis.

Illustration of MX2020 front-to-back air flow

Figure 1-41. Illustration of MX2020 front-to-back air flow

Line Card Compatibility

The MX2020 is compatible with all Trio-based MPC line cards; however, there will be no backwards compatibility with the first-generation DPC line cards. The caveat is that the MPC1E, MPC2E, and MPC3E line cards will require a special MX2020 Line Card Adapter. The MX2020 can support up to 20 Adapter Cards (ADC) to accommodate 20 MPC1E through MPC3E line cards. Because the MX2020 uses a newer-generation SFB with faster bandwidth, line cards that were designed to work with the SCB and SCBE must use the ADC in the MX2020.

The ADC is merely a shell that accepts MPC1E through MPC3E line cards in the front and converts power and switch fabric in the rear. Future line cards built specifically for the MX2020 will not require the ADC. Let’s take a look at the ADC status with the show chassis adc command:

dhanks@MX2020> show chassis adc
Slot  State                            Uptime
 3    Online 6 hours, 2 minutes, 52 seconds
 4    Online 6 hours, 2 minutes, 46 seconds
 8    Online 6 hours, 2 minutes, 39 seconds
 9    Online 6 hours, 2 minutes, 32 seconds
11    Online 6 hours, 2 minutes, 26 seconds
16    Online 6 hours, 2 minutes, 19 seconds
17    Online 6 hours, 2 minutes, 12 seconds
18    Online 6 hours, 2 minutes, 5 seconds

In this example, there are eight ADC cards in the MX2020. Let’s take a closer look at FPC3 and see what type of line card is installed:

dhanks@MX2020> show chassis hardware | find "FPC 3"
FPC 3            REV 22   750-028467   YE2679            MPC 3D 16x 10GE
  CPU            REV 09   711-029089   YE2832            AMPC PMB
  PIC 0                   BUILTIN      BUILTIN           4x 10GE(LAN) SFP+
    Xcvr 0       REV 01   740-031980   B10M00015         SFP+-10G-SR
    Xcvr 1       REV 01   740-021308   19T511101037      SFP+-10G-SR
    Xcvr 2       REV 01   740-031980   AHK01AS           SFP+-10G-SR
  PIC 1                   BUILTIN      BUILTIN           4x 10GE(LAN) SFP+
  PIC 2                   BUILTIN      BUILTIN           4x 10GE(LAN) SFP+
    Xcvr 0       REV 01   740-021308   19T511100867      SFP+-10G-SR
  PIC 3                   BUILTIN      BUILTIN           4x 10GE(LAN) SFP+

The MPC-3D-16X10GE-SFPP is installed into FPC3 using the ADC for compatibility. Let’s check the environmental status of the ADC installed into FPC3:

dhanks@MX2020> show chassis environment adc | find "ADC 3"
ADC 3 status:
  State                      Online
  Intake Temperature         34 degrees C / 93 degrees F
  Exhaust Temperature        46 degrees C / 114 degrees F
  ADC-XF1 Temperature        51 degrees C / 123 degrees F
  ADC-XF0 Temperature        61 degrees C / 141 degrees F

Each ADC has two chipsets, as shown in the example output: ADC-XF1 and ADC-XF2. These chipsets convert the switch fabric between the MX2020 SFB and the MPC1E through MPC3E line cards.

Aside from the simple ADC carrier to convert power and switch fabric, the MPC-3D-16X10GE-SFPP line card installed into FPC3 works just like a regular line card with no restrictions. Let’s just double check the interface names to be sure:

dhanks@MX2020> show interfaces terse | match xe-3
Interface               Admin Link Proto    Local                 Remote
xe-3/0/0                up    down
xe-3/0/1                up    down
xe-3/0/2                up    down
xe-3/0/3                up    down
xe-3/1/0                up    down
xe-3/1/1                up    down
xe-3/1/2                up    down
xe-3/1/3                up    down
xe-3/2/0                up    down
xe-3/2/1                up    down
xe-3/2/2                up    down
xe-3/2/3                up    down
xe-3/3/0                up    down
xe-3/3/1                up    down
xe-3/3/2                up    down
xe-3/3/3                up    down

Just as expected: the MPC-3D-16X10GE-SFPP line card has 16 ports of 10GE interfaces grouped into four PICs with four interfaces each.

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