Cisco Systems UBR900 Data Operations

Feature Overview

4Cisco IOS Release 12.0(7)T

In firewall mode, the Cisco uBR900 series cable access router provides a high-speed Internet

connection for an office’s local network while protecting the computers on the office network from

common attacks such as denial of service attacks and destructive Java applets, as well as real-time

alerts of such attacks.

The Small Office feature set can be optionally extended with support for IPSec encryption to ensure

that the traffic passed over the Internet cannot be intercepted. You can select either standard 56-bit

IPSec Network Security encryption or high-security 168-bit Triple Data Encryption Standard (DES)

encryption.

In addition to full DOCSIS 1.0 support and all of the functionality of the Easy IP feature set, the

Telecommuter feature set supports IPSec encryption and the Layer 2 Tunneling Protocol (L2TP),

which can establish secure high-speed Internet connections between employees’ homes and the

office local network.

IPSec is an IP security feature that provides robust authentications and encryption of IP packets for

the secure transmission of sensitive information over unprotected networks such as the Internet. You

can select either standard 56-bit IPSec Network Security encryption or high-security 168-bit Triple

Data Encryption Standard (DES) encryption.

L2TP is an extension of the Point-to-Point Protocol (PPP) that allows computers on different

physical networks to interoperate as if they were on the same local area network (LAN). These

features are important components for Virtual Private Networks (VPNs).

Note The Telecommuter feature set does not require the firewall feature set because the individual

telecommuter has a secure connection to the office network. The office network, however, should

implement a firewall for its own connection to the Internet.

Data Operations

Figure 1 illustrates a typical broadband data cable system. Data transmitted to a Cisco uBR900 series

cable access router from the service provider’s CMTS shares a 27 or 26 Mbps, 6 MHz data channel

in the 88 to 860 MHz range. The Cisco uBR900 series cable access router shares an upstream data

rate of up to 10 Mbps on a 200 kHz-wide to 3.2 MHz-wide channel in the 5 to 42 MHz range.

Note End-to-end throughput varies based on the design and loading of network components, the

mix of traffic, the processing speed and interface of the host server(s), the processing speed and local

Ethernet performance of the subscriber’s computer, as well as other parameters. Since the network

can be configured to support multiple levels of service to meet differing market price/performance

requirements, the subscriber’s service level agreement also affects throughput. DOCSIS further

contains some fundamental performance limitations because standards are designed to give a larger

number of customers good performance, rather than permitting a few users to consume the entire

capacity.