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Volatile Data in Routers and Appliances
Volatile data in routers and network appliances such as dedicated firewalls is very similar to that of a personal computer with one exception—a physical hard disk may not be present. All data is likely to be located in some type of Random Access Memory (RAM) or Non-Volatile RAM (NVRAM).
As an example of how many network appliances are designed, let’s look at the architecture of the standard Cisco® router. Each router, depending on the model, normally contains the basic configuration an investigator would expect in a personal computer: motherboard, CPU, memory, bus, and I/O interfaces.
These interfaces and expansion card slots can become complex in higher-end models. In a network device such as a Cisco router, the key point of difference between the router and a PC is the lack of physical hard disk. The hard disk is replaced by flash memory, which can be viewed as a solid-state disk containing nonvolatile data.
In Cisco routers, this flash memory is where a compressed copy of the Internetwork Operating System (IOS) image and other supporting files are kept. Volatile data such as the running IOS (operating system code pages) is kept in Dynamic RAM (DRAM) or Synchronous RAM (SRAM). In some cases the routing table or tables, statistics, local logs, and so on are also kept in DRAM/SRAM.
Volatile data in routers and network appliances such as dedicated firewalls is very similar to that of a personal computer with one exception—a physical hard disk may not be present. All data is likely to be located in some type of Random Access Memory (RAM) or Non-Volatile RAM (NVRAM).
As an example of how many network appliances are designed, let’s look at the architecture of the standard Cisco® router. Each router, depending on the model, normally contains the basic configuration an investigator would expect in a personal computer: motherboard, CPU, memory, bus, and I/O interfaces.
These interfaces and expansion card slots can become complex in higher-end models. In a network device such as a Cisco router, the key point of difference between the router and a PC is the lack of physical hard disk. The hard disk is replaced by flash memory, which can be viewed as a solid-state disk containing nonvolatile data.
In Cisco routers, this flash memory is where a compressed copy of the Internetwork Operating System (IOS) image and other supporting files are kept. Volatile data such as the running IOS (operating system code pages) is kept in Dynamic RAM (DRAM) or Synchronous RAM (SRAM). In some cases the routing table or tables, statistics, local logs, and so on are also kept in DRAM/SRAM.
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