How to distinguish between L3 switches and routers using Ethernet interconnected Wan

More and more Wan solutions are now using Ethernet overSDH. On the surface, L3 switches and traditional routers can meet the needs of Wan interconnection. Therefore, many partners and customers have this question, what is the difference between the two in the wide area network connection? The following are some of my opinions for your reference.
What is the difference between using a Cisco L3 switch and using a router as a WAN connection?
First, the network solution design cannot be limited to the layer of Route connection.
Nowadays, customers are more concerned about the security of the network itself and the application layer hosted by the network. The Ethernet network is used to improve the network speed, the spread and harm of any security attacks are also accelerated. In addition, more and more customers are concerned about the network ROI. If an IP communication system is deployed on a traditional routing network, the customer's work efficiency will be greatly improved and the production cost will be reduced.
Based on the above arguments, the author gives the following comparison:
1) Commonalities:
Both the L3 switch and the router can achieve Wan interconnection through Ethernet and use ACL to provide basic security access control;
2) Differences: The Packet Exchange Performance of Cisco routers cannot be compared with that of L3 switches. However, in terms of wide-area network connection, Cisco routers are better than L3 switches:
(I) Advanced Security Defense: the FW and IPS functions contained on Cisco routers can greatly prevent security attacks from Lan: TCP/UDP DoS attacks and SMTP attacks, provides security proxy and authentication services for Telnet, HTTP, and other applications, and provides comprehensive intrusion defense functions.
Ii) VPN deployment: Cisco routers support VPN services, GRE, NAT, and other applications. These applications are required for Wan interconnection, however, low-end L3 switches often do not have these features (because they are located in the LAN );
Iii) IP Communication Application Deployment: Cisco routers support both IPC and integrate SRST, CCME, And CUE. They can act as ip pbx and provide IP Phone call and voicemail functions. the vro supports the configuration of Various Voice interface cards, which greatly facilitates the deployment of VoIP, which are not available in L3 switches.
Iv) wireless LAN Integrated Application: Cisco routers can also support WDS of WLAN and provide the fast L2 Security roaming function. L3 switches do not;
V) other value-added applications: Cisco routers provide the Content Engine module to accelerate the speed of wide-area network services and use its URL filtering tool (N2H2/Smartfilter) to filter and control the capability of internal users to serve poor websites and websites unrelated to the company's business; to provide a network management module to analyze network traffic, etc, these value-added applications are also not available in L3 switches.

1. Ethernet Switching Technology Trend
2. Topic: typical configurations of common Switches
3. Topic: About route security configuration and security