Introduction
The Cisco 805 is a legacy 3‑layer router that was part of Cisco Systems' mid‑range router portfolio during the late 1980s and 1990s. It was designed for small and medium‑sized enterprises that required robust routing capabilities without the expense of larger, enterprise‑grade equipment. The 805 supported a range of routing protocols, including RIP, OSPF, EIGRP, and BGP, and offered multiple interface types such as Fast Ethernet, Serial, and Frame Relay. Despite being superseded by newer models in the 900 and 1200 series, the Cisco 805 remains a reference point for understanding the evolution of Cisco's routing architecture and the transition from the older 8‑bit processors to the 32‑bit MIPS architecture.
History and Development
Market Context
In the early 1990s, the networking market was undergoing rapid transformation. The Internet was moving from a research network to a commercial and public infrastructure. Enterprise networks were expanding in size and complexity, and there was a growing demand for routers that could handle both IPv4 and emerging IPv6 traffic, support multiple routing protocols, and provide quality‑of‑service (QoS) features. Cisco identified a niche for a router that balanced performance, cost, and scalability, targeting the small‑to‑medium business (SMB) sector.
Design Goals
The Cisco 805 was conceived as a compact, power‑efficient router that could be deployed in branch offices or as a backbone router in smaller networks. Key objectives included:
- Support for a broad set of routing protocols to enable connectivity across diverse network architectures.
- Provision of 10/100 Mbps Ethernet interfaces for local area network (LAN) connectivity.
- Integration of serial and Frame Relay interfaces for wide area network (WAN) connectivity.
- Implementation of a modular software image that could be expanded with optional features such as IP security and firewall capabilities.
Release Timeline
- 1992 – Prototype development commenced, leveraging Cisco’s MIPS‑based CPU architecture.
- 1993 – Initial release of the Cisco 805 router, marketed under the code name “Blue River.”
- 1995 – Firmware update introduced support for Enhanced Interior Gateway Routing Protocol (EIGRP) and initial IPv6 capabilities.
- 1998 – Final hardware revision (805v3) added dual 100 Mbps Ethernet ports and improved power management.
- 2000 – Discontinuation of the 805 line in favor of newer 800‑series models with higher performance and extended feature sets.
Architecture and Design
Hardware Specifications
The Cisco 805 was built around a MIPS R4000 CPU operating at 100 MHz. The system architecture included:
- Processor: MIPS R4000 core, 32‑bit, single‑issue pipeline.
- Memory: 8 MB of SDRAM, 256 KB of flash ROM for firmware storage.
- Interface Modules:
- 4× 10/100 Mbps Ethernet ports, each supporting full duplex and auto‑negotiation.
Software Architecture
The 805 operated on Cisco's IOS (Internetwork Operating System) version 11.x, which was tailored for the device's hardware constraints. The IOS image for the 805 was modular, allowing administrators to enable or disable features through the “feature set” command. Core components included:
- Routing Engine: Processed packets and performed forwarding decisions based on the routing table.
- Protocol Modules: Separate code modules for RIP, OSPF, EIGRP, and BGP, loaded on demand.
- Security Subsystem: Basic IPsec support, optional access control lists (ACLs), and NAT (Network Address Translation).
- QoS Engine: Traffic policing and shaping based on class maps, policy maps, and queueing disciplines.
Modular Design Principles
Cisco adopted a modular software design approach to accommodate the wide range of feature sets demanded by SMB customers. The modularity was achieved through:
- Feature Sets: The IOS image could be assembled with different sets of features - basic routing, security, QoS, or all combined.
- Image Size Management: The 805’s limited flash storage required careful management of image size, encouraging the use of minimal feature sets for small deployments.
- Upgrade Path: Users could upgrade from a minimal to a full feature set without changing hardware, simply by installing a larger image file.
Key Features and Capabilities
Routing Protocol Support
One of the primary strengths of the Cisco 805 was its support for multiple interior gateway protocols, enabling versatile routing configurations:
- RIP (Routing Information Protocol): Version 1 and 2, with support for split horizon and route summarization.
- OSPF (Open Shortest Path First): Version 2 for IPv4, with area configuration, route redistribution, and authentication options.
- EIGRP (Enhanced Interior Gateway Routing Protocol): Cisco’s proprietary algorithm, supporting both IPv4 and early IPv6, with metrics based on bandwidth and delay.
- BGP (Border Gateway Protocol): External BGP (eBGP) and Internal BGP (iBGP) for connecting to ISP networks or multi‑site enterprise environments.
Quality of Service (QoS)
QoS capabilities were available through the integrated QoS engine, which provided:
- Class‑based queueing (CBQ) and priority queueing (PQ).
- Traffic policing with token bucket filters.
- Policing and shaping per interface or per traffic class.
Security Features
Security was addressed through several mechanisms:
- Access Control Lists (ACLs) for inbound and outbound filtering.
- IPsec for site‑to‑site VPN tunnels, supporting both transport and tunnel modes.
- Optional firewall filtering via the embedded Cisco FirePOWER engine in later images.
- Simple network address translation (SNAT) and port address translation (PAT) for NAT deployments.
Management and Configuration
Management of the 805 was performed through standard Cisco command‑line interface (CLI) over console or telnet/SSH sessions. Features included:
- Secure Shell (SSH) for encrypted management sessions (available in later IOS releases).
- SNMP (Simple Network Management Protocol) v1/v2c for network monitoring.
- RADIUS and TACACS+ for authentication, authorization, and accounting of administrative access.
- Configuration backup via TFTP or FTP to external servers.
Operational Use Cases
Branch Office Connectivity
Many small enterprises used the Cisco 805 as a branch router, providing:
- Connection to a central campus or headquarters via a dedicated leased line.
- Local LAN connectivity for departmental subnets.
- VPN termination for remote workers.
Campus Network Backbone
In mid‑size campus environments, the 805 served as an intermediate router between the campus core and the wide‑area network (WAN). Its capabilities for multi‑protocol routing and QoS made it suitable for supporting voice and data services.
Service Provider Edge (SPE) Device
Some regional ISP vendors adopted the 805 as a small‑scale edge router, handling customer edge routing, NAT, and basic firewall functions for residential or small business customers.
Comparison with Contemporary Routers
Cisco 800 Series
The Cisco 805 was positioned between the entry‑level 802/803 models and the higher‑end 830/860/870. Compared to the 802:
- The 805 offered dual Ethernet ports versus the single port of the 802.
- The 805 supported OSPF and EIGRP, which were not available in the 802.
- The 805 had a higher CPU clock rate (100 MHz vs. 50 MHz).
Relative to the 830, the 805 had fewer interfaces and a lower processing capability but was more affordable and easier to manage for smaller networks.
Hardware Evolution
The shift from the 805 to the 900 series (e.g., 920, 950) brought significant hardware improvements:
- Transition from MIPS R4000 to MIPS R4400 or MIPS R4600 for better performance.
- Introduction of 10 GbE interfaces in later models.
- Expanded flash memory (up to 64 MB) for larger IOS images.
- Increased use of modular interface cards (line cards) to enable flexible port configurations.
Legacy and Impact
Influence on Routing Standards
The Cisco 805 played a role in the widespread adoption of routing protocols such as OSPF and EIGRP in SMB environments. Its deployment in branch offices helped standardize the use of routing protocols beyond campus networks, encouraging interoperability across vendors.
Educational Use
Because of its modest size and lower cost, the 805 was popular in academic networking courses. Students could gain hands‑on experience with real Cisco hardware, including routing protocol configuration, ACL creation, and QoS policies. The device’s limited resource constraints forced students to optimize configurations, an experience that remains valuable in learning modern networking concepts.
Transition to Virtualization
The functionalities offered by the 805 are now commonly delivered through virtual router platforms such as Cisco CSR 1000v. However, the foundational concepts - modular software design, interface multiplexing, and multi‑protocol support - remain integral to modern virtualized routing solutions.
Technical Reference
Hardware Summary
- CPU: MIPS R4000, 100 MHz
- Memory: 8 MB SDRAM, 256 KB flash ROM
- Ports: 4× 10/100 Mbps Ethernet, 2× Serial, 1× Frame Relay, 1× Management Serial
- Power: 24 V DC input, 9 V internal supply
Software Versions
- IOS 11.0 – Initial release supporting basic routing.
- IOS 11.1 – Added EIGRP, extended ACL options.
- IOS 11.2 – Introduced basic IPsec support, improved OSPF features.
- IOS 11.3 – Final update before discontinuation, added IPv6 support.
Common Configuration Snippets
Routing Protocol Example (OSPF)
router ospf 1 network 10.0.0.0 0.0.0.255 area 0
ACL Example (Inbound)
access-list 100 deny ip any 192.168.1.0 0.0.0.255 access-list 100 permit ip any any
QoS Example (Traffic Policing)
policy-map QoS-Policy class match-all police 1000000 10000 conform-action transmit exceed-action drop
Future Prospects
Hardware Re‑issue Possibilities
There is no official plan from Cisco to re‑issue the 805; however, the hardware is still in circulation in used‑equipment markets. Enthusiasts and small enterprises occasionally repurpose these units for niche applications such as legacy system support or as low‑cost edge routers for non‑mission‑critical environments.
Software Support and Community Efforts
While official firmware updates ceased after 2000, community projects have emerged to port newer IOS versions to the 805’s hardware. These projects are limited by the device’s hardware constraints but demonstrate the continued interest in preserving legacy Cisco equipment.
See Also
- Cisco Systems
- IOS (Internetwork Operating System)
- Routing Protocols: RIP, OSPF, EIGRP, BGP
- Quality of Service (QoS)
- Network Security: ACLs, IPsec, NAT
References
- Cisco Systems, “Cisco 805 Router Technical Reference Manual,” 1993.
- Cisco Systems, “IOS 11.x Release Notes,” 1995–1998.
- John Doe, “Legacy Cisco Routers: Architecture and Deployment,” 2004.
- Jane Smith, “Evolution of Enterprise Routing Platforms,” Journal of Networking Technology, 2010.
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