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This chapter describes the Cisco Cache Engine and its specification and considerations for using the system. Before you install the Cache Engine, take time to carefully plan the placement of the Cache Engine on your networks. This helps ensure that you receive the maximum benefit of caching web traffic.
The Cache Engine is a special-purpose hardware/software carrier-class solution that has been designed from the ground up as a loosely coupled, multinode network system optimized to provide robust shared network caching.
The Cache Engine works with routers running Cisco IOS software with the Web Cache Communication Protocol (WCCP.) WCCP redirects HTTP traffic (traffic that uses TCP port 80) to a Cache Engine; the Cache Engine then manages the web request. See Appendix B, "Web Cache Communication Protocol Version 1" for more information on WCCP, Version 1. See Appendix C, "Web Cache Communication Protocol Version 2" for more information on WCCP, Version 2.
Thus, the Cache Engine works in tandem with a router to handle web traffic. This traffic includes user requests to view pages and graphics (objects) on World Wide Web servers, whether internal or external to your network, and the replies to those requests.
When a user requests an object from a web server, the router first sends the request to a Cache Engine. If the Cache Engine has a copy of the requested object in storage, the Cache Engine sends the user the object. Otherwise, the Cache Engine gets the requested objects from the web server, stores a copy of the objects (caches them), and simultaneously forwards the objects on to the user.
By caching web objects in this manner, the Cache Engine can speed the satisfaction of user requests if more than one user wants to access the same objects. This also reduces the amount of traffic between your network and the Internet, potentially improving your overall network performance and optimizing your bandwidth usage.
Table 1-1 lists the specifications of the Cache Engine.
| Specifications | Model 505 | Model 550 |
|---|---|---|
Hard disk storage | One 9.1 GB ULTRA 2 LVD SCSI hard drive | Two 9.1 GB ULTRA 2 LVD SCSI hard drives |
Memory | 8-MB Flash memory 128-MB SDRAM 256-KB EPROM 512-KB L2 cache | 8-MB Flash memory 256-MB SDRAM 256-KB EPROM 512-KB L2 cache |
CPU | 266 MHz | 366 MHz |
Ethernet controller | Intel 82588
| Intel 82588
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Dimensions | Height: 1.72 inches (43.69 mm) Width: 17.5 inches (444.50 mm) Depth: 14.1 inches (358.14 mm) | Height: 1.72 inches (43.69 mm) Width: 17.5 inches (444.50 mm) Depth: 14.1 inches (358.14 mm) |
Weight | 11.2 pounds (5.08 kg) | 12.5 pounds (5.67 kg) |
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Current |
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Connectors | Console: One RJ-45 connector Network: Two 10/100 BaseTX Ethernet RJ-45 connectors
External SCSI: 68-pin High Density connector (ULTRA2 LVD)
Support for a maximum of 80 MBps data transfer | Console: One RJ-45 connector Network: Two 10/100 BaseTX Ethernet RJ-45 connectors
External SCSI: 68-pin High Density connector (ULTRA2 LVD)
Support for a maximum of 80 MBps data transfer |
Maximum station-to-station cabling distance | 10/100BaseTX Ethernet: Category 5 UTP: 328 ft (100 m) SCSI ULTRA2 LVD: 12 m maximum | 10/100BaseTX Ethernet: Category 5 UTP: 328 ft (100 m) SCSI ULTRA2 LVD: 12 m maximum |
LEDs | Power System LINK (x2) 100 Mbps (x2) Drive 0 Drive 1 4 SW Status | Power System LINK (x2) 100 Mbps (x2) Drive 0 Drive 1 4 SW Status |
Agency approvals | FCC Class A (47 CFR Part 15) EN 55022A Class B on shielded UTP VCCI Class A UL 1950 CSA-C22.2 No. 950 EN 60950 CE Mark | FCC Class A (47 CFR Part 15) EN 55022A Class B on shielded UTP VCCI Class A UL 1950 CSA-C22.2 No. 950 EN 60950 CE Mark |
Placement | Rack-mounted, mid, front or back (standard 19-inch and 24-inch racks) | Rack-mounted, mid, front or back (standard 19-inch and 24-inch racks) |
Temperature | Operating: 41° to 113°F (5° to 45°C) Nonoperating: -13 to 158°F (-25 to 70°C) | Operating: 41° to 113°F (5° to 45°C) Nonoperating: -13 to 158°F (-25 to 70°C) |
Operating humidity | 5 to 95%, noncondensing | 5 to 95%, noncondensing |
Posted: Fri Feb 1 16:45:54 PST 2002
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