Interface type
The types of interfaces that the router can support reflect the universality of the router. Common types of interfaces include: general serial interface (converted through cables to RS232 DTE/DCE interface, V.35 DTE/DCE interface, X.21 DTE/DCE interface, RS449 DTE/DCE interface and EIA530 DTE interface, etc.), 10M Ethernet interface, Fast Ethernet interface, 10/100 adaptive Ethernet interface, Gigabit Ethernet interface, ATM interface (2M, 25M, 155M, 633M, etc.), POS interface (155M, 622M, etc.), token ring interface, FDDI interface, E1/T1 interface, E3/T3 interface, ISDN interface, etc.
Number of slots available to users
This indicator refers to the number of slots that users can use in a modular router except for necessary system boards, clock boards, etc. and/or dedicated slots for system boards. Based on this indicator and the user board port density, the maximum number of ports supported by the router can be calculated.
CPU
Whether in low-end routers or high-end routers, the CPU is the heart of the router. Usually in low-end routers, the CPU is responsible for exchanging routing information, routing table search, and forwarding packets. In the above routers, the CPU's capabilities directly affect the router's throughput (routing table search time) and routing computing power (affecting network routing convergence time). In high-end routers, packet forwarding and table lookup are usually completed by ASIC chips, and the CPU only implements routing protocols, computing routing and distribution routing tables. Due to the development of technology, many of the work in routers can be implemented by hardware (special chips). CPU performance does not fully reflect router performance. Router performance is reflected in indicators such as router throughput, delay and routing computing capabilities.
Memory
A router may consist of multiple memory, such as Flash, DRAM, etc. Memory is used as storage configuration, router operating system, routing protocol software and other contents. In low- and mid-end routers, routing tables may be stored in memory. Generally speaking, the larger the router memory, the better (no consideration of price). However, similar to CPU capabilities, memory does not directly reflect the router's performance and capabilities. Because efficient algorithms and excellent software may greatly save memory.
Port density
This indicator reflects the integration of router production. Due to the different router size, this indicator should be converted into the number of ports per inch in the rack. But for the sake of intuition and convenience, it is usually possible to replace it with the maximum number of routers that support each port.
Routing Information Protocol (RIP)
RIP is a routing protocol based on distance vectors, and usually uses hop count as a measurement standard. RIP is an internal gateway protocol. Because RIP is simple to implement, it is the most widely used routing protocol. This protocol converges slowly and is generally used in smaller networks. The RIP protocol is specified in RFC 1058.
Policy routing method
In addition to using the destination address as the basis for routing, the router can also select a path for the packet based on the TOS field, source and destination port number (high-level application protocol). Policy routing can implement traffic engineering to a certain extent, allowing flows of different quality of service or data of different natures (voice, FTP) to take different paths.
Distance Vector Multicast Routing Protocol (DVMRP)
DVMRP is a multicast routing protocol based on distance vectors, and is basically developed based on RIP. DVMRP uses IGMP to exchange routes with neighbors
Full duplex line speed forwarding capability
The most basic and most important function of a router is packet forwarding. Forwarding packets at the same port rate is the biggest test of router packet forwarding capabilities. Full-duplex line speed forwarding capability refers to the bidirectional transmission on the router port at the minimum packet length (64 bytes over Ethernet, 40 bytes on the POS port) and the minimum packet interval (compliant with the protocol). This indicator is an important indicator of router performance.
Device Throughput
It refers to the equipment package forwarding capability and is an important indicator of equipment performance. The job of a router is to select routes according to IP packet header or MPLS marks, so the performance indicator is the number of forwarded packets per second. Device throughput is usually less than the sum of all port throughputs of the router.
Port Throughput
Port throughput refers to the port packet forwarding capability, which is usually measured by pps: packets per second, which is the router's packet forwarding capability on a certain port. Usually two interfaces for the same rate are tested. However, the test interface may be related to the interface location and relationship. For example, the throughput tested between ports on the same card may be different from the throughput value between ports on the same card.
Routing table capability
Routers usually rely on the established and maintained routing tables to decide how to forward. Routing table capability refers to the limit of the number of routing table entries contained in the routing table. Since routers that execute BGP protocol on the Internet usually have hundreds of thousands of routing table entries, this project is also an important reflection of router capabilities.
Backplate capability
Backplane capability is an internal implementation of the router. Backplane capabilities can be reflected in router throughput: backplane capabilities are usually greater than values calculated based on throughput and test package locations. However, the backplane capability can only be reflected in the design and generally cannot be tested.
QoS classification method
It refers to the information on which the router can distinguish the QoS is based. The simplest QoS classification can be based on ports. Similarly, routers can also distinguish packet priority based on link layer priority (as specified in 802.1Q), upper layer content (TOS field, source address, destination address, source port, destination port, etc.).
Group voice support method
In enterprises, router packet voice carrying capacity is very important. Between the remote office and the headquarters, routers that support packet voice can integrate telephone communication and data communication, effectively saving long-distance phone bills. In the current technical environment, packet voice can be divided into three types: using IP to carry packet voice, using ATM to carry voice, and using frame inheritance to carry voice. When using ATM to carry voice, there are two types: AAL1 and AAL2. AAL1 is circuit simulation, the technology is very mature but relatively high in cost. AAL2 technology is more advanced, but the current ATM interface is usually not supported. The frame inheritance and inheritance voice is also relatively mature and relatively low in cost. IP voice-bearing is currently more popular. Among the above technologies, the cost is the lowest, but it is difficult to ensure QoS of IP networks and the quality of call is difficult to ensure.
Voice compression capability
Voice compression is one of the keys to IP phones saving costs. G.723 and G.729 can usually be used. G.723 is recommended by ITU-T G.723.1 (1996), and the voice encoder is specified in the 5.3 and 6.3Kbps multimedia communication transmission dual-rate voice encoder. The compression is relatively high and the compression delay is relatively large. G.729 is specified in ITU-T Recommendation G.729 (1996), 8Kbps conjunction structure algebraic digital excitation linear prediction (CS-ACELP) speech coding. Low compression and better call quality.
Signaling support
The router E1 port may support multiple signaling: ISUP, TUP, China No. 1 signaling and DSS1. Routers that support ISUP, TUP or DSS1 signaling can effectively reduce the connection time. Telecom level IP telephone network settings
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Article entry: csh Editor in charge: cshIt is usually required to support No. 7 signaling. However, as a mid-to-low-end router, it usually only supports DSS1 and China No. 1 signaling.
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