Basic Small Branch Network System Assurance Guide
Basic Small Branch Network Overview
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Basic Small Branch Network Overview

Table Of Contents

Basic Small Branch Network Overview

Contents

Introduction

Small Branch Design Considerations

System Design

Topology

Cisco Platforms and Versions Evaluated

References and Recommended Reading


Basic Small Branch Network Overview


Revised: December 21, 2009

This chapter describes the Basic Small Branch Network design and components.

Contents

Introduction

Small Branch Design Considerations

System Design

Topology

Cisco Platforms and Versions Evaluated

References and Recommended Reading

Introduction

The Basic Small Branch Network enables enterprises with branch offices of up to 25 users to deploy high-value network services such as unified communication on top of a secure branch network infrastructure that is connected to a campus or data center core (central site) over a variety of WAN technologies. The goal of the Basic Small Branch Network is to make deployment of these services fast, simple, and predictable.

The Basic Small Branch Network is one of the Cisco Integrated Services Networks for the branch office. These networks focus on providing branch office deployment blueprints for connectivity, security, voice, and application optimization services integrated into the branch router. Integrated Services Branch Networks consist of three Services Ready Branch Networks, two Basic Branch Networks, and one Basic Branch Network, each corresponding to a different size branch office and branch router platform, as shown in Figure 1.

Figure 1 Integrated Services Branch Networks

The Integrated Services Branch Networks are implementations of the Cisco Enterprise Branch Architecture framework and focus on networking services directly integrated into the branch office router. The Framework is one component in the overall Cisco Service Oriented Network Architecture (Cisco SONA), which provides guidelines for designing advanced network capabilities into enterprise IT infrastructure. Leveraging elements of the Cisco Enterprise Branch Architecture Framework, the Cisco Integrated Services Branch Networks incorporate networking infrastructure components and the most common integrated services found in a typical branch office, as shown in the red box in Figure 2. All Integrated Services Networks have undergone an intensive system assurance test program and will be tested on an ongoing basis as individual components continue to evolve.

Figure 2 Common Integrated Services in Enterprise Branch Networks

This guide focuses on deployment of the Basic Small Branch Network. It provides design, implementation, and testing guidelines for the following features for a large branch network:

WAN services

LAN services

Network fundamentals

IP routing and addressing

Quality of service (QoS)

Security services

Infrastructure protection

Access control

Secure connectivity

Threat prevention, detection, and mitigation

Network management

Voice services

IP telephony with centralized call control

IP telephony with local call control

Traditional telephony and fax

The blueprint begins with a list of design criteria for a secure small branch office network that can be optimized for unified communications. The "System Design" section describes the network topology and network services that address these design criteria. The "System Implementation" chapter provides a step-by-step implementation of the topology and configuration of each service. Finally, testing methodology for the system is provided along with test cases and test results in the "System Testing" chapter. The "References and Recommended Reading" section lists additional detailed documents on the various technologies used in the Basic Small Branch Network.

For a list of tested platforms, interface cards, modules, and software versions, see the "Cisco Platforms and Versions Evaluated" section.

Small Branch Design Considerations

Today most enterprise resources are typically located at the corporate headquarters and accessed from a branch office over a private WAN. However, certain types of applications and services continue to be deployed in the branch office. To support them, a branch network must meet additional requirements beyond basic connectivity. For the small branch office, these requirements typically include security, manageability, and telephony. The Basic Small Branch Network has been designed to meet such requirements and offers two deployment options. One provides security services for a branch office of up to 25 users. The other provides security and voice services for a branch office of up to 15 users. The following are its main design criteria:

Branch Network Components

Branch Network Components for Voice-Enabled Basic Branch

WAN Services

LAN Services

Network Fundamentals

Security Services

Network Management

Voice Services

Branch Network Components

Up to 25 active users within the branch office

Multiple integrated network services deployed in the branch router

Minimal carbon footprint

Majority of corporate resources are centrally located

Branch Network Components for Voice-Enabled Basic Branch

Up to 15 active users within the branch office

Multiple integrated network services deployed in the branch router

Converged data, voice, and video network

Minimal carbon footprint

Majority of corporate resources are centrally located

Telephony that supports the following use cases:

Moderate call volume user

Heavy call volume user

Decision maker

Video-conferencing user

Conference room

WAN Services

Dedicated bandwidth ranging from 0.75 to 1.5 Mb/s to handle data, voice, and video traffic

Fast Ethernet, single T1, or fractional T1 dedicated lines to WAN service providers network

Traditional Layer 2 private WAN with various encapsulation options to guarantee privacy and reliability

or

Layer 3 Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) for increased flexibility and reduced bandwidth cost

or

Layer 2 Ethernet or MPLS VPN for greater control and simplified connectivity

LAN Services

Hierarchical network design to simplify deployment, troubleshooting, and management

Connectivity to branch devices at Fast Ethernet or Gigabit Ethernet speeds

Near-wire-speed performance between all devices

Power-over-Ethernet (PoE)

Network Fundamentals

High availability, rapid recovery, and disaster recovery

Rapid recovery in case of non-redundant component failure

Automatic switchover to backup WAN link that has a minimum one-quarter of the bandwidth of the primary WAN link

Ability to restore service within 24 hours in the event of a disaster

Quality of service (QoS)

Automatic application-specific traffic prioritization both within the branch office and across the enterprise WAN

Bandwidth management for WAN-based traffic

Provisions to mitigate denial of service (DoS) and worm attacks

Identification and classification of critical application flows for QoS

Additional Quality of Service (QoS) for the voice-enabled branch

Manual application-specific traffic prioritization both within the branch office and across the enterprise WAN

Provisions for IP telephony, business video, critical and bulk data applications

IP routing and addressing

Routing within the enterprise and between the branch and the service provider network

Direct Internet access from the branch

Support for multicast applications

Translation of private addresses and ports in order to access the Internet

Dynamic allocation of IP addresses for end devices

Security Services

Infrastructure protection

Physical securing of access to networking devices

Disabling of unused services that may be used to exploit the network

Authentication of routing protocol updates

Access control

Authentication and authorization services for controlling access to network resources

Logging capabilities for auditing access to network devices and resources

Integration with global access management system to enforce access privileges

Secure connectivity

Secure interoffice connectivity for full-mesh and hub-and-spoke WAN topologies

Secure access into the branch network for remote or home office workers

Voice, video, and data separation on the LAN

Separation of network management traffic

Access to the server in the branch by home office users

Threat protection, detection, and mitigation

Blocking of unauthorized traffic from entering or leaving the branch

Access to servers in the branch by home office users

Verification of source addresses for incoming traffic

Identification and mitigation of common DoS attacks and worms

Prevention of malicious attacks on the branch office network from outside

Prevention of attacks and security breaches from within the branch office

Network Management

Monitoring of networking services through a unified management console

Analysis of IP services and generation of data needed for verification of service level agreements

Ability to synchronize network time to accurately analyze network performance

Traffic monitoring and accounting

Common infrastructure for collecting and logging events generated by network devices

Ability to automate initial software installation and configuration of all network devices

Ability to automate reconfiguration of all network devices

Voice Services

Ability to use IP-based and traditional analog telephones in the branch network

Support for WAN-based (Toll Bypass), LAN-based (Private Exchange), and PSTN (Traditional) calling

Ability to regulate quantity of calls placed over the WAN

Support for voice and video calls

Local voice mail and auto attendant

Ability to use traditional analog fax devices

Support for conference calling

Transcoding of various voice codecs

Connectivity to emergency services

Support for multiple dial peers and plans

Music on hold for waiting callers

Capacity to support:

5:1 user-to-active call ratio

4:1 WAN-to-PSTN call ratio

4:1 WAN-to-LAN call ratio

2 percent of calls to be video

5 percent of calls to be conferencing calls

10 percent of calls resulting in a transcoding session

Survivable central-site call control

or

Local call control

System Design

Branch network design varies greatly from one enterprise to another. Each design reflects the size, location, cost constraints, and business requirements of the corresponding branch office. However, regardless of the network architecture, a set of common branch networking elements provides:

Network connectivity within the branch, to the Internet, and to the rest of the enterprise

Security for data residing in the branch or crossing the network

Unified network management and configuration

Voice and fax services to support reliable, converged VoIP and POTS communication

To help enterprises address these common connectivity, security, management, and voice needs, the Basic Small Branch Network assembles the most important and common of these elements in a single, rigorously tested design. The goals of this design are to provide assurance that the various features interoperate and to provide a starting point for customization. The design focuses only on the services that integrate directly into the branch office router. Alternative designs that feature external appliances and provide the same functionality as the Basic Small Branch Network are equally viable.

For guidance on implementation of such designs, see the Cisco enterprise branch architecture documents at:

http://www.cisco.com/en/US/netsol/ns656/networking_solutions_program_home.html.

The following components and fundamental connectivity, security, and management services were tested in the Basic Small Branch Network:

Branch Network Components

Branch Network Components for Voice-Enabled Basic Branch

WAN Services

LAN Services

Network Fundamentals

Security Services

Management Services

Voice Services

Branch Network Components

Cisco 1941 Integrated Services Router (ISR)

Cisco Catalyst 2960 Switch

Branch Network Components for Voice-Enabled Basic Branch

Cisco 1861 ISR

Cisco Catalyst 2960 Switch

Cisco Unified IP Phones 7942G, 7945G, 7961G, 7962G, 7965G, 7971G, and 7985G

Cisco Unified IP Conference Station 7936

WAN Services

Dedicated leased lines through service provider network

A T1 lines with Multilink Frame Relay, Multilink Point-to-Point Protocol (MLPPP) encapsulation

A ½ T1 line with PPP or Frame Relay (FR) encapsulation

Fast Ethernet line shaped to 1.5 Mb/s

Virtual lines through service provider network provisioned at provider edge (PE) devices

Frame Relay service

Connectivity to service provider's PE device

A ½ T1 line with Frame Relay (FR) encapsulation

Layer 3 Virtual Private Network (L3VPN)

Connectivity to service provider's PE device

A T1 line with PPP encapsulation

A ½ T1 line with PPP encapsulation

Layer 2 Virtual Private Wire Service (VPWS)

Connectivity to service provider's PE device:

A T1 line with PPP encapsulation

A ½ T1 line with PPP encapsulation

A T1 line with Frame Relay (FR) encapsulation

A ½ T1 line with Frame Relay (FR) encapsulation

Fast Ethernet line shaped to 1.5 Mb/s

LAN Services

Power-over-Ethernet (PoE)

Fast Ethernet connectivity

Network Fundamentals

High availability, rapid recovery, and disaster recovery

Backup WAN link with Symmetric High-Speed Digital Subscriber Line (SHDSL)

Routers and switches with modular, field-replaceable components

IP addressing and routing

Network Address Translation (NAT)/Port Address Translation (PAT)

Open Shortest Path First (OSPF)

Enhanced Interior Gateway Routing Protocol (EIGRP)

Routing Information Protocol (RIP) Version 2

Dynamic Host Configuration Protocol (DHCP)

Multicast

QoS

Automatic QoS (AutoQoS)

Shaping on the egress WAN interface

Class of service (CoS) to DSCP mapping with Weighted Round Robin (WRR) queuing on LAN switches

DSCP re-marking on LAN switches

Rate policing on LAN switches

Congestion-only queuing on LAN switches

Network Based Application Recognition (NBAR)

Additional QoS for the voice-enabled branch

Hierarchical 8-class QoS Model using Low Latency Queuing (LLQ), Class-Based Weighted Fair Queuing (CBWFQ), Weighted Random Early Detection (WRED), and Differentiated Services Code Point (DSCP)-WRED on the router

Policing of voice and video traffic on the egress WAN interface

Security Services

Perimeter protection

Disabling of unused services

Console timeouts

Password protection

Secure Shell (SSH) access

Routing protocol security

Access control

Authentication, Authorization, and Accounting (AAA) with RADIUS and TACACS+

Syslog

Secure connectivity

Encryption with 3 DES (Data Encryption Standard) and 256-bit Advanced Encryption Standard (AES)

Key exchange with Diffie-Hellman Group 2

Data integrity with Message Digest 5 (MD5) and Secure Hash Algorithm 1 (SHA-1)

Preshared key (PSK)

IP Security (IPsec) Dynamic Multipoint VPN (DMVPN)

IPsec Group Encrypted Transport VPN (GETVPN)

802.1Q virtual LANs (VLANs)

WebVPN (SSL VPN)

Threat Protection, Detection, and Mitigation

Cisco IOS Intrusion Prevention System (IPS) with advanced signature set

Zone-based Cisco IOS firewall

802.1x

Port security

IP source guard

PortFast bridge protocol data unit (BPDU) guard

DHCP snooping

Dynamic Address Resolution Protocol (ARP) inspection

Standard and extended Access Control Lists (ACLs)

Unicast Reverse Path Forwarding (uRPF)

DoS attack and worm detection and mitigation with NBAR

Management Services

Simple Network Management Protocol (SNMPv3)

Cisco Configuration Professional (CCP)

Network Time Protocol (NTP)

IP service level agreements (SLAs)

NetFlow version 5

Syslog

Cisco Configuration Engine (CCE)

Voice Services

Cisco Unified Communications Manager (Cisco Unified CM)

Survivable Remote Site Telephony (Cisco Unified SRST)

Cisco Unified Communications Manager Express (Cisco Unified CME)

Voice Gateway

Cisco Unity Express

Resource Reservation Protocol (RSVP) agent

Analog lines for PSTN connectivity

Analog device connectivity

Emergency services

Packet voice digital signal processing modules (PVDM)

Fax pass-through

Fax T.38 relay

Transcoding

Conferencing

G.711 and G.729a codecs

cRTP

Music on hold (MOH)

Topology

The Basic Small Branch Network provides security, and network manageability for the small branch, and integrates the various network services into the branch office router. As Figure 3 shows, there are two topologies.

One topology consists of a single Cisco 1861 series ISR for WAN termination, services aggregation, and LAN connectivity, and a Catalyst 2960 access switch for additional LAN connectivity. This topology features security and voice services.

The other topology consists of a single Cisco 1941 series ISR for WAN termination, services aggregation, and a Catalyst 2960 access switch for LAN connectivity. This topology only features security but supports a larger number of users.

Both topologies meet the criteria highlighted in the "Small Branch Design Considerations" section.

Figure 3 Basic Small Branch Network Topology for Security and Voice Services

Figure 4 Basic Small Branch Network Topology for Security Services

Cisco Platforms and Versions Evaluated

The information in this document is based on the hardware and software listed in Table 1 and Table 2.

Table 1 Hardware Configurations 

Platform
Configuration

Cisco 1861

HWIC-1T1/E1, PVDM3-32, 128 MB DRAM, 64 MB flash

Cisco IOS Release 12.4(20)T2-Advanced Enterprise Services Image

Cisco 1941

EHWIC, 512MB DRAM, 256MB flash

Cisco IOS Release 15.0(1)M-Advanced Enterprise Services Image

Catalyst 2960

WS-C2960G-24-TC-L, 64 MB DRAM, 32 MB flash

Cisco IOS Release 12.2(25)SEE4 - IP Services Image

Catalyst 2960

WS-C2960PD-8TT-L, WS-C2960-8TC-L, 64 MB DRAM, 32 MB flash

Cisco IOS Release 12.2(25)SEE4 - IP Services Image


Table 2 Hardware and Software Versions 

Component
Version

Cisco Unified IP Phones 7942G, 7945G, 7961G, 7962G, 7965G, 7971G, 7985G

8.3.x

Cisco Unified Conference Station 7936

1.2(1)

Cisco Unified Communications Manager Express (Cisco Unified CME)

4.1

Cisco Unified Survivable Remote Site Telephony (Cisco Unified SRST)

4.1

Cisco IOS Intrusion Prevention System
(Cisco IOS IPS)

Cisco Configuration Engine (CCE)

5.0

3.0


References and Recommended Reading

For more information on topics described in this guide, see the following documents:

Cisco WAFS Benchmark Tool for Microsoft Office Applications Installation and Configuration Note

High Availability Campus Network Design—Routed Access Layer Using EIGRP or OSPF

LAN Baseline Architecture Branch Office Network Reference Design Guide

Enterprise QoS Solution Reference Network Design Guide

Business Ready Teleworker Design Guide

Enterprise Branch Security Design Guide

Enhanced IP Resiliency Using Cisco Stateful Network Address Translation

Stateful Failover for IPSec

The following information is referenced in this guide:

Cisco Design Zone for Security

Cisco IOS Configuration Fundamentals Command Reference

Cisco IOS Debug Command Reference

Cisco IOS IP Addressing Services Command Reference

Cisco IOS IP Application Services Command Reference

Cisco IOS IP Multicast Command Reference

Cisco IOS IP Routing Protocols Command Reference

Cisco IOS LAN Switching Command Reference

Cisco IOS NetFlow Command Reference

Cisco IOS Quality of Service Solutions Command Reference

Cisco IOS Security Command Reference

Cisco IOS Voice Command Reference

Cisco Solution Reference Network Design Guides

Basic Small Branch Network Quick Start Guide

Support-Cisco Systems