Installing QFX3008-I Interconnect Device Mounting Hardware on Four-Post Racks or Cabinets

Before you install the QFX3008-I Interconnect device in a four-post rack or cabinet, you must first install mounting hardware and remove the center-mounting brackets from the chassis.

Note: In a rack, the device uses 21 U. You can mount two QFX3008-I Interconnect devices on a 42 U rack provided that the racks meet the strength requirements to support the combined weight of the devices. If you are mounting two QFX3008-I Interconnect devices on a rack, mount the first device on the bottom of the rack.

There are two styles of mounting hardware for the QFX3008-I Interconnect device. One style of mounting hardware uses a large shelf that spans the four rack posts and rests on a rear support bracket. The other style of mounting hardware uses a large shelf on the front posts, a smaller shelf on the rear posts, and spacer bars mounted to the rack posts to ensure proper alignment of rack-mounting screws. Figure 1 and Figure 2 depict the different styles of mounting hardware.

Depending on which style of mounting hardware you have, perform one of the first two tasks, then remove the center-mounting brackets from the chassis:

• Installing Four-Post Mounting Shelf and Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Installing Spacer Bars and Shelves for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Removing the Adjustable Center-Mounting Brackets for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Installing Four-Post Mounting Shelf and Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Figure 1 depicts the four-post mounting shelf and rear support bracket mounting hardware. If the mounting hardware included with your QFX3008-I Interconnect device instead includes spacer bars and two shelves, see Installing Spacer Bars and Shelves for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting.

Figure 1: Installing Four-Post Mounting Shelf and Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

For a four-post rack or cabinet, Table 1 specifies the holes in which you insert mounting screws (an X indicates a mounting hole location), and cage nuts if needed. The hole distances are relative to one of the standard “U” divisions on the rack.

Table 1: Four-Post Mounting Shelf and Rear Support Bracket Hole Locations

Hole	Distance Above U Division		Four-Post Mounting Shelf	Rear Support Bracket
6	3.25 in. (8.3 cm)	1.86 U		X
5	2.63 in. (6.7 cm)	1.5 U		X
4	2 in. (5.1 cm)	1.14 U		X
3	1.5 in. (3.8 cm)	0.86 U	X	X
2	0.88 in. (2.2 cm)	0.5 U	X	X
1	0.25 in. (0.6 cm)	0.14 U	X	X

• Installing Cage Nuts for the Four-Post Mounting Shelf and Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Installing the Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Installing the Four-Post Mounting Shelf for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Installing Cage Nuts for the Four-Post Mounting Shelf and Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

For racks without threaded holes, you must install cage nuts on the rack or cabinet rails in the locations specified in Table 1 (an X indicates a mounting hole location).

Before you begin, ensure that you have 18 cage nuts appropriate for your rack or cabinet.

1. On the front rack or cabinet, install cage nuts in the holes specified in Table 1 for the large shelf.
2. On the rear rack or cabinet, install cage nuts in the holes specified in Table 1 for the support bracket.

Installing the Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

To mount the chassis on a four-post rack or cabinet, you must first install the four-post mounting shelf and rear support bracket on the rack or cabinet.

• A Phillips (+) screwdriver, number 2 or 3, depending on the size of your rack mounting screws (not provided)
• 12 mounting screws appropriate for your rack to attach the rear support bracket to the rack (not provided)

1. On the rear of each rear rack rail, partially insert a mounting screw 1 U below where you intend to install the chassis.
2. Install the rear support bracket on the rear of the rear rack rails. Rest the bottom slot of the rear support bracket on a mounting screw. The rear support bracket extends toward the center of the rack.
3. Partially insert screws into the open holes in the rear support bracket. Tighten all the screws.

Installing the Four-Post Mounting Shelf for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

To mount the chassis on a four-post rack or cabinet, you must first install the four-post rack mounting shelf and rear support bracket on the rack or cabinet.

• A Phillips (+) screwdriver, number 2 or 3, depending on the size of your rack mounting screws (not provided)
• Six mounting screws appropriate for your rack to attach the four-post rack mounting shelf to the rack (not provided)
• UNC 8/32 flat-head screws to attach the four-post rack mounting shelf to the rear support bracket (provided)

1. On the front of each front rack rail, partially insert a mounting screw 1 U below where you intend to install the chassis.
2. Install the four-post rack mounting shelf on the front rack rails. Rest the front of the four-post rack mounting shelf on the mounting screws you installed on the front rack rails. Rest the back of the four-post rack mounting shelf on top of the rear support bracket.
3. Partially insert screws into the open holes in the four-post rack mounting shelf. Tighten all the screws.
4. Fasten the four-post mounting shelf to the rear support bracket by partially inserting the flat-head screws provided in the accessory kit into the open holes on top of the four-post mounting shelf. Several holes are provided on top of the shelf. Two holes on each side of the shelf will align with the holes in the rear support bracket. Tighten all the screws.

Installing Spacer Bars and Shelves for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Figure 2 depicts the spacer bars and small and large shelf mounting hardware. If the mounting hardware included with your QFX3008-I Interconnect device instead includes a large shelf that spans the four posts, and rear support bracket, see Installing Four-Post Mounting Shelf and Rear Support Bracket for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting.

Figure 2: Installing Spacer Bar and Shelves for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

For a four-post rack or cabinet, Table 2 specifies the holes in which you insert mounting screws (an X indicates a mounting hole location), and cage nuts if needed. The hole distances are relative to one of the standard “U” divisions on the rack. For reference, the bottom of all mounting shelves is at 0.04 in. (0.02 U) above a U division.

Table 2: Four-Post Rack or Cabinet Mounting Hole Locations

Hole	Distance Above U Division		Large Shelf	Spacer Bars	Small Shelf
51	29.51 in. (74.9 cm)	16.86 U		X
42	24.26 in. (61.6 cm)	13.86 U		X
33	19.01 in. (48.3 cm)	10.86 U		X
30	17.26 in. (43.8 cm)	9.86 U	X
24	13.76 in. (34.9 cm)	7.86 U		X
15	8.51 in. (21.6 cm)	4.86 U		X
6	3.26 in. (8.3 cm)	1.86 U		X
3	1.51 in. (3.8 cm)	0.86 U			X
2	0.88 in. (2.2 cm)	0.50 U	X		X
1	0.25 in. (0.6 cm)	0.14 U			X

• Installing Cage Nuts for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Installing the Small Mounting Shelf for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting
• Installing the Large Mounting Shelf and Spacer Bars for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Installing Cage Nuts for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

For racks without threaded holes, you must install cage nuts on the rack or cabinet rails in the locations specified in Table 2 (an X indicates a mounting hole location).

Before you begin, ensure that you have 22 cage nuts appropriate for your rack or cabinet.

1. On the front rack or cabinet, install cage nuts in the holes specified in Table 2 for the large shelf and the spacer bars.
2. On the rear rack or cabinet, install cage nuts in the holes specified in Table 2 for the small shelf.

Installing the Small Mounting Shelf for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

To mount the chassis on a four-post rack or cabinet, you must first install the mounting shelves and spacer bars on the rack or cabinet.

• A Phillips (+) screwdriver, number 2 or 3, depending on the size of your rack mounting screws
• Six mounting screws appropriate for your rack to attach the small mounting shelf to the rack

1. On the back of each rear rack rail, partially insert a mounting screw into the lowest hole specified in Table 2 for the small shelf.
2. Install the small shelf on the back rack rails. Rest the bottom slot of each ear on a mounting screw. The small shelf installs on the back of the rear rails, extending toward the center of the rack. The bottom of the small shelf should align with the bottom of the large shelf.
3. Partially insert screws into the open holes in the ears of the small shelf. Tighten all the screws.

Installing the Large Mounting Shelf and Spacer Bars for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

To mount the chassis on a four-post rack or cabinet, you must first install the mounting shelves and spacer bars on the rack or cabinet.

• A Phillips (+) screwdriver, number 2 or 3, depending on the size of your rack mounting screws
• 16 mounting screws appropriate for your rack to attach the large mounting shelf and spacer bars to the rack

1. On the front of each front rack rail, partially insert a mounting screw into the lowest hole specified in Table 2 for the large shelf.
2. Install the large shelf on the front rack rails. Rest the bottom slot of each ear on a mounting screw.
3. Partially insert a mounting screw into the top hole in each ear of the large shelf. Tighten all the screws.
4. The device is shipped with each spacer bar attached to the rear of each front-mounting flange. Remove each spacer bar by removing the seven screws that fasten the spacer bar to the front-mounting bracket.
5. Place one of the spacer bars over an ear of the installed large shelf. Position the notch in the rear of the spacer bar so the upper part of the bar is flush with the rack rail and the lower part is flush with the ear of the shelf.
6. Insert a mounting screw into each of the nonthreaded holes in the recesses of the spacer bar to secure the spacer bar.
7. Repeat Step 5 and Step 6 for the other spacer bar.
8. Tighten all the screws.

Removing the Adjustable Center-Mounting Brackets for QFX3008-I Interconnect Device Four-Post Rack or Cabinet Mounting

Before you begin, ensure that you have a number 2 Phillips (+) screwdriver.

1. Loosen the three screws at the top and bottom of each bracket.
2. Remove the center-mounting brackets.

   Tip: Save the center-mounting brackets and screws in case you need to move the device to a two-post rack at a later time.