The purpose of this article is to identify the several kinds of edge routers that are now appearing on the market. Edge-specific routers must be able to handle the functionalities described below with ease. Edge routers can serve in a number of different functions and be of a number of different types. Edge routers are located at the demarcation point between the edge network and a WAN of some kind. They are distinguished from core routers whose functionality is focused on processing speeds. Core routers—almost by definition—are deployed in small numbers; sometimes just a single router.
- By contrast, edge routers are installed in multiples, distributed across the networking space, embody more smarts and have advanced security features. Edge routers are more concerned with this kind of functionality than with raw speed. Although edge routers are almost always dedicated hardware devices, it is worth noting that edge routers could be embodied in servers running some kind of specialist software. The use of edge routers helps to improve the quality of service (QoS) in edge networks because they mitigate bottlenecks and slowdowns of traffic flow in the network. Edge routers also typically provide the functionality for remote access by (for example) off-premises employees/customers.
- Like other routers, edge routers may have either static or dynamic routing capabilities. However, the primary focus with edge routers, of course, is inbound traffic, which is offloaded into the edge network for processing. Edge routers must have high availability and redundancy. They must contain sufficient traffic management to prevent congestion and packet loss and may also contain multiplexing capabilities to increase network efficiency.
- There are potentially many data rates that can be used for traffic into the edge network. There may still be some instances where GigE/copper is used. However, before too long, the data rate associated with all edge routers will be 10G and 100G and interconnections will be rapidly fiber. Transition to 400G is eventually a possibility but has yet to happen in any great degree.
- As the network grows, edge network capacity may get tapped out and the number and capabilities of edge routers in the network must then be reviewed and added to. As each new edge computing network at least one more edge computing router will be purchased and deployed.
- Since edge routers will be the first point of contact of the device with the outside world, edge routers are of considerable strategic importance and are at the core of edge computing networks. They are critical to the edge networking market boom that is taking place right now. Because they are smart and have many capabilities, they also provide many ways that vendors can distinguish themselves in the burgeoning edge computing marketplace
Beyond the edge/core distinction and its commercial implications are the distinctions among edge routers themselves. In the past conventional routers have been neither powerful nor efficient enough to handle large amounts of complex data generated by latency sensitive spaces. Nonetheless, otherwise conventional routers have been deployed as “edge routers,” which is why the term “edge router” predates products that are specifically designed and branded for use in edge computing networks.
The purpose of this article is to identify the several kinds of edge routers that are now appearing on the market. Edge-specific routers must be able to handle the functionalities described above with ease. Edge routers can serve in a number of different functions and be of a number of different types.
Edge Router Types
Subscriber edge routers: Subscriber edge routers are used especially in small business networks and in consumer/residential networks and have a WAN-facing interface to an Internet Service Provider (ISP). Subscriber edge routers (also sometimes called a customer edge router) are located at the edge of the subscriber’s network and are typically used in an (enterprise) organization. This type of router is distinguished by the fact that it is configured to broadcast BGP externally.
Label edge routers: Multiprotocol Label Switching (MPLS) is an established routing technique that directs data from one node to the next based on short path labels rather than long network addresses. Thus, avoiding complex lookups in a routing table and speeding up traffic in the network. Label edge routers are used at the edge of MPLS and really should be considered as gateways. (See the next Chapter.)
Branch routers: Branch routers are used—as their name suggests—in a remote branch of the enterprise’s network. A remote branch is a piece of the network that has been architected as a VLAN within a particular WAN. Branch routers are often located at the edge of the WAN and therefore may be referred to as edge routers.
Inter-provider border router: A BGP router for interconnecting ISPs that maintains BGP sessions with other BGP routers in ISP Autonomous Systems. Inter-provider border routers may not entirely qualify as edge routers but are sometimes included under this heading.
White box routers: A white box router is the polar opposite of a branded product, not just in sense of lacking labelling, but also in terms of a relative lack of support. It might appeal to businesses seeking bargain basement shoppers for edge routers – but probably not the smallest businesses. This is because white box routers have limited amount of documentation or even a limited amount of software.
In other words, white box edge routers are not for the feint hearted. But for those with the experience the white box approach may also be easier to customize for the end user. That said, branded routers have garnered more attention and acceptance than white box routers, especially among service providers who worry about the reliability of white box offerings. To re-phrase the old adage originally about IBM—no one ever got fired for choosing Cisco, HPE and Dell EMC in the edge computing routers segment.
Security for Edge Routers
A final note: Security is a big part of the edge story. Edge routers are a crucial part of the edge firewall. They also provide access control and need to be configured to hand over workloads to other routers to provide for the eventuality of router failure. Indeed, edge network security has become a key area of opportunity and is being treated very seriously by IT experts. There is even one company that is building a box that uses quantum encryption to secure edge routers.
To ensure security, edge routers can either be configured with tools that include access control lists and they can be purchased with built-in support for firewalls. This enables more advanced security safeguards, including VPN tunnels and signature matching through intrusion prevention systems and intrusion detection systems.
Edge routers will play a fundamental role as more services and applications begin to be managed on an organization’s network edge rather than in its data center or in the cloud. Services considered suitable for edge router management include wireless capabilities often built into network edge devices, Dynamic Host Configuration Protocol (DHCP) services and domain name system DNS services.