Pro d u c t Bu lle t in No . 2 2 5 4
Cisco 1 0 0 0 0 S e r ie s Router
®
The Cisco 10000 Series Router introduces
Bro a d b a n d Ag g r e g a t io n
new forwarding hardware, interface
The term “broadband” covers many access
technologies, including high-speed,
®
modules, and Cisco IOS Software. The
application and utility of the platform has
expanded, offering exciting opportunities
for service providers in the areas of service
definition and reduced operational
expenditure. The focus of the Cisco 10000
Series remains at the edge of the service
provider network.
fixed-access circuits and wireless solutions.
For the purposes of this document,
broadband access is defined as subscriber
connections (business and residential)
accessing the service provider network over
DSL technologies. The Cisco 10000 Series
does not physically terminate DSL circuits
(this is the role of a DSL access multiplexer
[DSLAM]). Its role is to aggregate the many
thousands of ATM virtual circuits between
central office locations and a service
provider’s IP network.
The network edge has seen transformation
over the past years, with ever-increasing
demands on scalability, performance,
availability, and cost reductions. With its
new capabilities, the Cisco 10000 Series is
positioned to lead this market and define
the next wave of services and solutions.
Ethernet is another broadband technology.
Long-range Ethernet is emerging as an
alternative to DSL technology in many
metropolitan regions throughout the world
It is likely to appear as an alternative
transport medium for DSLAMs competing
with ATM.
The Cisco 1000 Series Performance
Routing Engine (PRE-2) offers a quantum
leap in scalability, performance, and
features over its predecessor (the PRE-1).
Coupled with the introduction of OC-48c/
STM-16c uplink modules, the solution is
positioned for higher-speed, higher-density
edge applications. The latest Cisco IOS
Software expands the Cisco 10000 Series
legacy in high-density leased-line and
Multiprotocol Label Switching (MPLS)
applications, to include a full-featured
broadband aggregation suite.
Ethernet is placed under the “broadband”
umbrella The Cisco 10000 Series offers
aggregation services for subscribers arriving
through traditional ATM broadband as
well as Ethernet broadband. With a rich
history in ATM connectivity and services,
the Cisco 10000 Series is optimized for
ATM-based broadband aggregation,
offering world-class scalability,
This document provides a guideline to
applications best suited for the Cisco 10000
Series with its latest enhancements.
performance, and features.
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Page 1 of 12
C is c o 1 0 0 0 0 S e r ie s A p p lic a t io n G u id e
Ge n e ra l Ove rvie w o f Bro a d b a n d Re m o te Acce s s S e rve r
The Cisco 10000 Series provides aggregation and connectivity services between the service provider’s access network
and the core IP network (Figure 1).
Fig u re 1
Service Provider Network Architecture
ATM Network
Cisco
10000
Series
IP Network
Core
DSL
DSLAM
Access
Subscriber
Edge
The access network consists of two main elements: DSL connections between the central office and customer
premises, and an ATM network connecting central offices to the service provider points of presence (POPs). The
access network is responsible for delivering subscriber connections in bulk to the service provider’s IP edge.
The core network usually consists of high-speed routers meshed together with high-speed optical circuits, providing
connectivity between regional POPs and peering points for Internet access.
The Cisco 10000 Series performs a pivotal role in the aggregation and termination of access technologies,
authentication services, and the switching and routing of IP packets to and from the core.
Ba s e lin e Att rib u te s fo r t h e Cis co 10000 S e rie s Bro a d b a n d Re m o te Acce s s Ag g re ga to r
ATM services—A full spectrum of ATM interfaces is available from DS3/E3 copper through to OC-12/STM-4
high-speed optical. Interface choice is coupled with industry-leading densities and the highest scalability of virtual
circuits. The Cisco 10000 Series offers several ATM service classes, including unspecified bit rate (UBR); UBR+;
variable bit rate, non-real time (VBR-nrt); and constant bit rate (CBR) with scalable, accurate shaping at both the
virtual circuit and virtual path layers.
Scalable provisioning services—Industry-leading authentication, authorization, and accounting (AAA) and Remote
Authentication Dial-In User Services (RADIUS) provisioning of bulk configurations with the “Virtual Circuit Range”
application. Zero-touch provisioning of virtual circuits with the “Auto-Configure” application.
Widest range of high-touch services—Using the Cisco 10000 Series Parallel Express Forwarding (PXF) adaptive
architecture, many per-virtual circuit services are available with zero effect on system performance or scalability.
From per-virtual circuit access control lists (ACLs) through IP multicast to extensive IP quality of service (QoS), the
Cisco 10000 Series continues to lead the industry with high-value embedded services.
High availability—The Cisco 10000 Series has set the standard with high-availability features for the edge leased-line
aggregation space. Much of the same technology and applications are used for broadband, enabling service providers
to confidently scale subscriber sessions and performance attributes without the fear of prolonged network outages.
As the concentration of subscriber aggregation on the Cisco 10000 Series increases, the requirement for advanced
high-availability features becomes greater.
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Bro a d b a n d A r c h it e c t u r e s a n d A p p lic a t io n s
RFC 1483/ 2668 a n d Re m o te Brid ge En ca p s u la t io n
RFC 1483/2668 and Remote Bridge Encapsulation (RBE) are synonymous with ATM virtual circuits—they are
traditionally used by service providers that “terminate” subscriber virtual circuits at the network edge and “route”
traffic into the core for Internet or VPN services. The main difference between the two protocols is in the area of IP
management. RFC 1483/2668 relies heavily on manual provisioning of addresses and routes per subscriber, while
RBE uses Dynamic Host Configuration Protocol (DHCP) technology to automate the provisioning of addresses and
routes. RBE is much simpler to provision and offers far greater scalability attributes than RFC 1483/2668.
Many service providers use these protocols for business-class Internet access, particularly where cheaper DSL access
circuits are replacing leased lines. The point-to-point and “always-on” nature of these services make them ideal
candidates for such access protocols. Both protocols are used extensively throughout the broadband application
space, with an installed base of many millions of subscribers.
The subscriber experience is often defined at the broadband remote access server (BRAS) by using ATM or IP-level
rate-limiting capabilities. Both ATM traffic shaping and IP policing/shaping are supported on the Cisco 10000 Series
platform, offering scalable and accurate solutions for both environments (Figure 2).
Fig u re 2
RFC1483/2668 and RBE
DHCP
Cisco
10000
Series
Subscriber
ATM
IP Network
DSLAM
IP
IP
RFC 1483/2668 or RBE
ATM
The Cisco 10000 Series offers a comprehensive Cisco IOS Software feature set that has proven reliability,
interoperability, scalability, and performance for both applications. RFC 1483/2668 is also used extensively for
leased-line applications. The Cisco 10000 Series has supported this protocol for more than three years, and has
thousands of ports terminated.
Po in t -to -Po in t Pro to co l Te rm in a t io n a n d Ag g re ga t io n
Two main types of Point-to-Point Protocol (PPP) are used throughout the broadband space: PPP over ATM (PPPoA)
and PPP over Ethernet (PPPoE). PPPoE can be transported on either ATM virtual circuits (PPPoEoA) or over Ethernet
(PPPoEoE). In this section, all subscriber connections will arrive on ATM virtual circuits.
PPP has the flexibility to span two broadband architectures. The PPP Termination and Aggregation (PTA) method is
typical for retail applications, and the “tunneled” method is typical for the wholesale architecture. This section will
concentrate on the PTA solution (Figure 3).
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Fig u re 3
PTA
RADIUS/AAA
Cisco
10000
Series
Subscriber
ATM
IP Network
DSLAM
IP
IP
PPPoA or PPPoEoA
ATM
Service providers that wish to terminate the ATM and PPP access protocols and route subscribers’ IP packets into the
core network can choose either the PPPoA or PPPoEoA protocols in the PTA architecture. The PPPoE protocol uses
a PPP client on the subscriber PC and offers the ability to run multiple PCs (or sessions) over a single ATM virtual
circuit. Conversely, the PPPoA protocol offloads the client to the customer premises equipment (CPE). This makes
the configuration of the PC much simpler, but only a single PPP session is supported per DSL connection.
PPPoX protocols are synonymous with the residential broadband market. This popular protocol provides a
well-understood method for subscriber authentication and IP address management. It has a strong legacy in the dial
market; consequently, many service providers are comfortable with its deployment. It also offers many features that
enhance scalability and flexibility of service offerings. The Cisco 10000 Series supports a comprehensive PPPoX
application suite, including extensive AAA/RADIUS attributes to allow flexible and scalable provisioning of services.
One advantage of PPPoX with authentication is service selection. Here, a subscriber can choose a destination
network or service attributes by selecting different logons or using a Web-based application. This capability is known
as Service Selection Gateway.
Laye r 2 Tu n n e lin g Pro to co l Arch ite ctu re s
Many service providers offer access to DSL-connected subscribers for the purposes of wholesale services. In other
words, they give subscriber connections to the Internet service provider (ISP) for a percentage of the subscriber’s
monthly subscription. In some cases, a provider will offer both retail and wholesale services. Retail services are
usually reserved for a service provider’s own ISP and will use a PTA architecture, while wholesale services are offered
for alternative ISPs and use tunneling technologies such as Layer 2 Tunneling Protocol (L2TP).
L2TP technology allows the carrier to present subscriber PPP sessions in bulk to the alternative ISP at a given
remote location, and offloads authentication and IP address management services to the destination ISP. In the L2TP
model, there are two main devices: the L2TP access concentrator (LAC) and the L2TP network server (LNS). The
Cisco 10000 Series is usually configured as an LAC.
The LAC is situated in the carrier’s POP and provides aggregation for the Layer 2 access medium (such as ATM). It
also provides a PPP switching service for subscriber sessions into the appropriate ISP’s L2TP tunnel (Figure 4). After
the session arrives at the destination ISP’s LNS, the PPP session is fully authenticated and IP services are started.
Subscriber IP packets from the LNS are routed to the Internet.
The wholesale provider has little to do with subscriber connections. The main purpose of this architecture is for mass
transportation of sessions from the POP to the ISP LNS.
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Fig u re 4
L2TP Tunneled Architecture
RADIUS/AAA
Cisco
RADIUS/AAA
10000
Series
Subscriber
ATM
IP Network
DSLAM
IP
LAC
LNS
IP/PPP
PPPoA or PPPoEoA
ATM
L2TP
The Cisco 10000 Series operates as a highly scalable LAC with a comprehensive set of PPP, AAA/RADIUS, and L2TP
attributes. In many cases, an ISP will contract the service provider to dictate the service rate for the subscriber. This
is usually implemented by ATM traffic shaping capabilities on the Cisco 10000 Series. A single LAC can support
subscriber sessions for many remote ISPs, and it is common to provision a unique L2TP tunnel per destination ISP.
Re m o te Acce s s to MPLS
Remote Access to MPLS (RA-MPLS) offers service providers an alternative to L2TP for the provisioning of wholesale
services. Instead of building unique L2TP tunnels per ISP, a unique VPN per ISP is provisioned over an MPLS core
(Figure 5). Layer 2 access protocols are terminated at the service provider’s edge and placed into the appropriate
VPN. Subscriber traffic is routed through the VPN to the destination ISP’s network, and then onto the Internet.
Fig u re 5
RA-MPLS
RADIUS/AAA
Cisco
RADIUS/AAA
10000
Series
Subscriber
ATM
IP Network
DSLAM
IP
P
P
P
P
PE
PE
IP
RFC 1483/RBE or PPPoX
ATM
MPLS VPN
The Cisco 10000 Series operates as a highly flexible provider edge MPLS device, supporting the widest range of Layer
2 encapsulations. It offers an array of per-VPN services, including Hot Standby Router Protocol (HSRP), AAA/
RADIUS, and DHCP.
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Le a s e d -Lin e Ag g r e g a t io n —G e n e r a l
The Cisco 10000 Series has provided leased-line aggregation services for tens of thousands of business customers and
hundreds of carriers (Figure 6). The provider edge is the dividing line between the various access technologies and
networks used to present customer connections to the carrier and the core IP transport network used for Internet or
VPN connectivity.
Fig u re 6
Leased-Line Architecture
TDM/SONET
ATM
Cisco
IP Network
10000
Series
Frame Relay
Access
Edge
Core
The Cisco 10000 Series provides several services at the edge, from Layer 2 circuit termination to advanced switching
and IP routing, along with many IP services.
Ba s e lin e Att rib u te s fo r t h e Cis co 10000 S e rie s Le a s e d -Lin e Ag g re ga to r
Interface diversity and density—Offers one of the broadest ranges of physical and logical interfaces in the industry,
from low-speed copper to high-speed optical channelized. All major worldwide interfaces are supported, enabling
the global service provider to select a single product for worldwide deployments. Using high-speed channelized
interfaces, the Cisco 10000 Series is able to boast the highest interface densities in the industry.
High-performance IP services—Using the Cisco 10000 Series PXF adaptive processing architecture, the range of IP
services continues to expand as the product and market matures. The Cisco 1000 Series Performance Routing Engine
(PRE-2) expands the Cisco 10000 Series link efficiency mechanisms to include Multilink Frame Relay, and many
other IP services have been enhanced over the PRE-1 implementation.
Rich MPLS feature set—Many service providers are deploying VPN-based solutions for additional revenue growth
in 2003 and beyond. The Cisco 10000 Series has proven its versatility, performance, and availability as a
next-generation provider edge router. The PRE-2/Full Sail release builds on this feature set to expand and increase
performance in this important application space
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Le a s e d -Lin e Ag g r e g a t io n A r c h it e c t u r e s a n d A p p lic a t io n s
Ch a n n e lize d Ag g re ga t io n Arch ite ctu re
The Cisco 10000 Series was introduced to the service provider market more than three years ago. From the start, it
has focused on the aggregation of low-speed, very-high-density leased-line circuits by using channelized interfaces
(Figure 7).
Fig u re 7
Channelized Architecture
Channelized
Interface
T1/E1
Cisco
10000
Series
IP Network
TDM/SONET
IP
IP
PPP or HDLC
SONET/SDH
The Cisco 10000 Series offers the widest suite of channelized modules, ranging from copper E1/T1 to optical O-12/
STM-4, allowing the Cisco 10000 Series the diversity for all leased-line applications. Recent channelization
enhancements to the optical modules help ensure worldwide coverage of configuration options. In a typical Cisco
10000 Series application, the provider usually situates the aggregator in a centrally located POP and backhauls
individual customer connections from central offices across the SONET/SDH networks. Add-drop multiplexers are
devices at either end of the optical network that provide aggregation of low-speed customer connections (T1/E1) and
aggregation into higher-order optical interfaces in the central POP. Popular Layer 2 encapsulations include PPP and
High-Level Data Link Control (HDLC), both with comprehensive support on the platform. Numerous IP services
are fully supported over channelized interfaces, including IP QoS, ACLs, IP multicast, and security services.
Fra m e Re lay Ag g re ga t io n
Frame Relay continues to dominate service provider markets in many regions and is the preferred technology for
Layer 2 VPNs. Over the past three years, many providers have taken advantage of their investment in Frame Relay
networks for overlay IP services (Figure 8).
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Fig u re 8
Frame Relay Architecture
Clear Channel
Interface
Business
Customer
Cisco
10000
Series
T1/E1
IP Network
Frame Relay
IP
IP
Frame Relay/DLC1
SONET/SDH
Many service providers offer IP Internet access and VPN products over existing Frame Relay access networks. Frame
Relay packet switched networks allow flexibility to build in contention and to better dimension infrastructure
resources based on traffic profiles, allowing better economies of scale. When aggregating Frame Relay circuits, the
Cisco 10000 Series is usually located in a central POP and connects to local switch nodes through copper or optical
interfaces. Typically, these connections are effected with nonchannelized interfaces. Frame Relay data-link
connection identifiers (DLCIs) are terminated on the Cisco 10000 Series with customer IP traffic routed through the
core network. Frame Relay encapsulation is supported on the full range of packet interfaces, including channelized
and nonchannelized modules. Numerous Frame Relay options and services are supported on the platform, including
traffic shaping and QoS.
ATM Ag g re ga t io n
ATM is prevalent in many incumbent local exchange carrier (ILEC) and PTT access networks, and many providers
use the technology as the foundation for multiservice platforms. Over the past several years, ATM has been used to
provide transport services for many applications, including backhaul for DSL services and leased-line emulation for
Internet and VPN services.
Fig u re 9
ATM Architecture
ATM
Interface
Business
Customer
Cisco
10000
Series
T1/E1
IP Network
ATM
IP
IP
RFC 1483
SONET/SDH
When used as an ATM aggregator, the Cisco 10000 Series is usually placed in a central POP and connected to a local
ATM switching node through optical interfaces. ATM virtual circuits are terminated on the device, and customer IP
traffic destined for the Internet or VPN is routed onto the core network.
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Page 9 of 12
The Cisco 10000 Series offers a full range of ATM interfaces, from DS3/E3 copper through OC-12/STM-4. The
platform supports ATM classes of service (CoSs), including UBR, UBR+, VBR-nrt, and CBR with extensive IP QoS
to ATM CoS interworking. A rich ATM feature set is supported, including accurate and scalable traffic shaping as
well as operations, administration, and maintenance (OAM) facilities.
Et h e rn e t Ag g re ga t io n
Ethernet is becoming more prevalent in metropolitan areas throughout the world, with many providers now offering
high-speed Internet and VPN access over local fiber-optic networks (Figure 10).
Fig u re 10
Ethernet Architecture
Gigabit
Ethernet
Business
Customer
Cisco
10000
Series
Ethernet
IP Network
IP
IP
Ethernet
SONET/SDH
Many enterprise customers use Ethernet technology for the “hub” site within a VPN network. “Spoke” sites are
generally connected to the service provider’s infrastructure with lower speed fixed circuits, such as those mentioned
previously. Customer connections are usually defined as 802.1Q virtual LAN (VLAN) logical interfaces under the
main Ethernet interface. The Cisco 10000 Series supports both Gigabit and Fast Ethernet interfaces with a rich set
of high-value IP services, including QoS and ACLs.
M P LS P ro v id e r Ed g e A p p lic a t io n s
Fig u re 11
MPLS Architecture
Customer
Edge
Cisco 10000
Series
Office 1
(VPN-A)
MPLS Core
VPN-A
VPN-B
Cisco 10000
Series
Office 2
(VPN-B)
Provider Edge
Cisco 10000
Series
Customer
Edge
Provider
Edge
Office 3
(VPN-A)
IP Network
MPLS VPN
Provider Edge
Office 4
(VPN-B)
Access Protocol
IP
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Most providers now offer Layer 3 VPN services as service offering of higher value than Internet access. MPLS
technology has allowed providers to target small to medium-sized businesses for outsourced VPN services. The
“build once, sell many” approach of the network design provides scalability and flexibility with respect to VPN
products and services. MPLS provider edge functions and a valuable array of associated features and services are
offered on the Cisco 10000 Series, spanning all interfaces and encapsulations from low-speed broadband to
traditional leased-line applications to high-speed Ethernet.
C o m b in e d Bro a d b a n d a n d Le a s e d -Lin e A p p lic a t io n s
Fig u re 12
A Combined Leased-Line and Broadband Architecture
Broadband Protocols
Cisco 10000
VPN
Series
Ethernet
Internet
Acess
Lease-Line Protocols
The demarcation between leased-line and broadband applications has become less clear over the past few years. DSL
circuits are competing in the traditional leased-line space, with many service providers offering Internet and VPN
services over these lower-cost alternatives to dedicated TDM. The role of the leased-line aggregator has been
expanded to include the termination of many traditional broadband interfaces and encapsulations. In today’s market,
the provider is continuously looking at ways to reduce costs and consolidate the number of edge products.
Combining leased-line and business-class DSL access is one option that many providers are introducing.
C o n c lu s io n
The introduction of the Cisco 10000 Series Performance Routing Engine (PRE-2) and associated line cards greatly
expands the utility of the Cisco 10000 Series across numerous service provider edge applications. The introduction
of scalable broadband services and the enhancements to the leased-line application position the Cisco 10000 Series
with Performance Routing Engine (PRE-2) as the market leader. The importance of leased-line and broadband
applications in a single edge device is likely to increase over the coming years, as service providers continue to look
at ways to consolidate infrastructure costs. The Cisco 10000 Series is best positioned to take advantage of the “new
edge” application with increased flexibility, performance, scalability, and availability.
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The Netherlands
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Fax: 31 0 20 357 1100
Americas Headquarters
Cisco Systems, Inc.
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Tel: 408 526-7660
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