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Expanding Capacity of Wide Area Networks at Remote and Mobile Sites
Multisite and global organizations today are facing several unique wide area network (WAN) challenges: the need to provide employees with instant access to centrally located information, the requirement to continuously back up and replicate mission-critical data to centrally managed data centers, the desire to provide satisfactory experience for IP phone and video communication, and the mandate to control bandwidth costs without sacrificing application availability and performance.
The Network Capacity Expansion System (NCE) is designed to help organizations address these challenges. Cisco NCE is a transport layer performance enhancing proxy (PEP) that increases the amount of available bandwidth at small to midsized branch offices and remote locations. It is designed to cost-effectively accelerate data transfer over the WAN by overcoming bandwidth and latency limitations. With NCE, multisite organizations get more data through and more value out of their existing WAN links.
Building on the strengths of the award-winning Cisco® integrated services routers (ISRs), Cisco NCE (Figure 1) is a small-footprint cost-effective module that transparently integrates into the ISR and natively uses capabilities of Cisco IOS® Software. With millions deployed worldwide, ISRs support the needs of multisite organizations that want to integrate advanced network services, such as NCE, into their remote site networks.
Figure 1. Network Capacity Expansion Advanced Integration Module with Cisco 1841 Integrated Services Router
The NCE Advantage
Designed to meet the needs of small and midsize remote sites, NCE focuses on three primary areas:
Throughput
Bandwidth specifies the maximum data transfer rate achievable on a WAN link. Latency, congestion, and packet loss determine the actual transfer rate (throughput). Cisco NCE uses two techniques to take throughput past the bandwidth limit: virtual bandwidth expansion and improved bandwidth utilization. Compression and packet-bundling algorithms increase effective bandwidth. Packet flow control and TCP optimization mitigate effects of congestion and latency to improve utilization of available bandwidth. The combined effect of these technologies results in a dramatic expansion of available WAN link capacity and enables extremely fast data transfer rates over the WAN.
Integration
Cisco NCE is a hardware extension of Cisco IOS Software and therefore tightly integrated into the network fabric. Such a close integration helps ensure that bandwidth optimizations and routing decisions are happening simultaneously without the added overhead of another interception. The tight integration has the added benefit of minimal configuration and once deployed requires no monitoring. Moreover, NCE is directly integrated into the Cisco Express Forwarding switching path, helping ensure complete transparency to other network services and all security provisions. Finally, NCE has been built ground up for ISRs and leverages the internal ISR hardware architecture.
Cost-Effectiveness
Cisco NCE performs no application-specific traffic optimization and is not classified as a WAN optimization controller (WOC). Cisco Wide Area Application Services (WAAS) fall into this product category, providing additional benefits. However, by focusing on the root causes of poor WAN throughput-limited bandwidth and network latency, eliminating complexities associated with vendor-specific application optimizations, and keeping costs low-NCE offers unbeatable price for performance, simplicity, and transparency. Designed to meet the needs of small and medium-sized remote sites, NCE is easy to use and maintain and uses the ISR for a low total cost of ownership.
Product Description
Cisco NCE acts as a transparent PEP (Figure 2) that terminates sender's TCP session locally, compresses and bundles the sender's data, sends the data to a remote peer encapsulated in a Stream Control Transmission Protocol (SCTP), unbundles and decompresses the data, and establishes a new TCP session remotely to deliver the data to its destination.
For remote and mobile sites, NCE is available in the Advanced Integration Module (AIM) form factor that is supported on all the modular ISRs, including the Cisco 1841, 2801, 2811, 2821, 2851, 3825, and 3845 Integrated Services Routers. There are two AIM configurations differing by the amount of outbound bandwidth supported.
Figure 2. Network Capacity Expansion System PEP Architecture
Cisco NCE is a symmetric solution that requires a pair of peer devices between end nodes. Each NCE module is capable of simultaneously increasing throughput for multiple peers, allowing hub-to-spoke and meshed deployments. For central office (headend) aggregation, NCE is available in the Network Module Extended (NME) form factor that is supported on the Cisco 3825 and 3845 ISRs. Table 1 summarizes the various supported NCE configurations.
Table 1. Supported Cisco NCE Configurations
Compression Increases Effective Bandwidth
Cisco NCE implements several compression techniques to overcome bandwidth limitations: payload compression, redundant header elimination, and efficient packet packing. For payload compression, NCE uses hardware implementation of the open standard Deflate algorithm with dynamic Huffman coding that preserves compression dictionaries across multiple packets. Payload compression yields 3:1 to 10:1 compression on standard benchmarks (Standard Canterbury Corpus). For redundant header elimination, NCE multiplexes several TCP sessions into a single SCTP stream, substituting TCP headers with the much smaller SCTP "chunk" identifiers. Finally, for efficient packet packing, NCE tightly bundles multiple compressed packets into the path maximum transmission unit (MTU), helping to ensure that no partially filled data link layer frame is sent across the WAN.
Transport Optimization Improves Bandwidth Utilization
Cisco NCE implements several optimization techniques to mitigate the effects of latency, packet loss and congestion: TCP protocol optimization and packet flow control. For TCP optimization, NCE transparently splices SCTP streams into TCP sessions that connect end nodes. The open standard SCTP inherits all the benefits of TCP, adds reliability features, and was designed ground up to overcome inefficiencies inherent in TCP. The use of SCTP to encapsulate traffic leads to a significant improvement in bandwidth utilization. For packet flow control, NCE paces WAN-bound traffic to match the prevailing WAN conditions, helping to ensure that packets are not dropped because of congestion.
Deployment Is Simple and Fast
Deploying NCE takes minutes. Various options are available for headend configuration depending on the number of remote sites and bandwidth dedicated to each site. (See Figure 3.)
Figure 3. Sample NCE Deployment
Performance
Although actual throughput gain depends on the specifics of a traffic profile, on standard file sets NCE has consistently demonstrated increase in effective bandwidth by more than 400 percent (Figure 4).
Figure 4. NCE Throughput Gain for Typical Remote Site
Features
Table 2. Cisco NCE Feature List
Product Specifications
Table 3. Cisco NCE Module Specifications
Ordering Information
To place an order, visit the Cisco ordering home page. Table 4 gives ordering information.
Table 4. Part Numbers for Cisco NCE Modules and Software
Service and Support
Cisco offers a wide range of services programs to accelerate customer success. These innovative services programs are delivered through a unique combination of people, processes, tools, and partners, resulting in high levels of customer satisfaction. Cisco Services help you protect your network investment, optimize network operations, and prepare your network for new applications to extend network intelligence and the power of your business. For more information about Cisco Services, refer to Cisco Technical Support Services or Cisco Advanced Services.
For More Information
For more information about Cisco NCE solutions, visit http://www.cisco.com/go/nce or contact your local Cisco account representative. For more information about Cisco integrated services routers, visit http://www.cisco.com/go/isr or contact your local Cisco account representative.