Router type
The form is mainly comparable to whether the router is a modular structure. The router of the modular structure is generally scalable, which can support a variety of port types, such as Ethernet interfaces, fast Ethernet interfaces, high-speed serial ports, etc., the number of various types of ports is generally optional. The price is usually more expensive. Fixed configuration router is poorly scalable, only for fixed types and numbers of ports, general price is cheap.
Router configuration
Interface type
Level the router supports the type of interface, reflecting the versatility of the router. Common interface types are: universal serial interface (converted to RS232 DTE / DCE interface, V.35 DTE / DCE interface, X.21 DTE / DTE interface, RS449 DTE / DCE interface, 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 loop, FDDI interface, E1 / T1 interface, E3 / T3 interface, ISDN interface, etc.
User available slots
This indicator refers to the number of slots that can be used in the modular router, except for the CPU board, the clock plate, and the like. According to this indicator and the user board port density can calculate the maximum number of ports supported by the router.
CPU
Regardless of the low-end router or in the high-end router, the CPU is the heart of the router. Usually in the medium and low-end routers, the CPU is responsible for switching routing information, routing table lookups, and forwarding packets. In the above routers, the CPU's ability directly affects the throughput of the router (routing table lookup time) and routing computing power (affecting network routing convergence time). In high-end routers, usually packet forwarding and surfract tables are done by ASIC chip, and the CPU only implements routing protocols, calculating routing, and distribution routing tables. Due to the development of technology, many of the work in routers can be implemented by hardware (special chips). The CPU performance does not completely reflect the performance of router. Router performance is embodied by the indicators such as router throughput, delay and routing capacity.
RAM
Various memory, such as Flash, DRAM, etc. Memory is used as a storage configuration, router operating system, routing protocol software, etc. In the medium and low-end routers, the routing table may be stored in memory. Generally, the router memory is, the better (no price). But similar to CPU capabilities, memory also does not directly reflect the performance and ability of routers. Because efficient algorithms and excellent software may greatly save memory.
Port density
This indicator reflects the integration of router making. Since the router is different, the indicator should be folded into the number of ports per inch of the rack. But for intuitive and convenient, the router can usually use the maximum number of each port supported.
Routing protocol support
Routing Information Protocol (RIP)
RIP is a routing protocol based on distance vectors, usually utilizing hops as a metering standard. RIP is an internal gateway protocol. Since the RIP implementation is simple, it is the most widely used routing protocol. The protocol converges slowly, generally used in small-scale networks. The RIP protocol is specified in RFC 1058.
Routing Information Protocol version 2 (RIPv2)
This protocol is RIP's improved version, allowing more information to be carried with RIP. The address mask (supporting CIDR), the next hop address, optional authentication information, etc. are added based on RIP. This version is regulated in RFC 1723.
Open Shortest Path Priority Protocol version 2 (OSPFv2)
The protocol is a link-based routing protocol that is designed for IP development as an IP development, as a subsequent internal gateway protocol for RIP. The role of OSPF is the minimum price route, multi-same path calculation and load balancing. OSPF has two major features of openness and use SPF algorithms.
"Intermediate System - Intermediate System" Agreement (ISIS)
The ISIS protocol is also a link-based routing protocol. The protocol is proposed by ISO, which is originally used in the OSI network environment, and then modified to run in a dual environment. This protocol is similar to the OSPF protocol, which can be used for large-scale IP networks as internal gateway protocols. Edge Gateway Agreement (BGP4)
The BGP protocol is a domain routing protocol for replacing EGP. BGP4 is the most popular and unique optional autonomous domain routing protocol on the current IP online. This version protocol supports CIDR and can use the routing aggregation mechanism to greatly reduce the routing table. The BGP4 protocol can use a variety of properties to flexibly control the routing strategy.
802.3, 802.1q support
802.3 is the standard of IEEE for Ethernet. The router that supports the Ethernet interface must meet the 802.3 protocol. 802.1q is the standard of IEEE to the virtual network. A router interface that meets 802.1q can support multiple VLANs on the same physical interface.
Support for IPv6
Future IP networks may be a network using IPv6. Since the emergence of the Web causes the development of Internet explosive, the user of the IP network increases rapidly, and the IP address is unprecedented, so IPv6 is proposed. IPv6 first to solve the problem is to expand address space, while also adding authentication and encryption of authentication and encryption in IP layers to define stream tags (Flow Label) for real-time applications. However, due to the huge inertia of the market and the effective application of unchecked addressing (CIDR), IPv6 has not been widely used in IPv6. But as the business increases, the development of the Internet is inevitable using IPv6.
Support for protocol other than IP
In addition to supporting IP protocol, router devices can also support protocols such as IPX, DECNET, AppleTalk. These agreements have a certain application abroad, and there are fewer applications in my country, and it is generally not considered.
Source site route support, transparent bridge
The address routing means that the router is not based on the destination address of the IP packet when the router is selected (usually according to the destination address), and is selected according to the source address of the IP package. The source site route is one of the policy routing. General routers should be supported. Transparent bridge refers to the function of performing bridges in a transparent bridge. No routing inspection of the data package, only MAC frame bridges.
Strategy routing
In addition to the basis of the selection of the destination address, the router can select the path according to the TOS field, source and destination port number (high-level application protocol). Strategy Routing can achieve traffic engineering to a certain extent, bring different paths of different service quality or different nature (voice, ftp).
PPP, MLPPP
The PPP protocol is an important protocol in the Internet protocol: Early networks are connected by routers using PPP protocol points, and most users use PPP access. Therefore, all routers with serial port should support PPP protocols and as preferred. MLPPP refers to a bundle of multiple PPP links.
PPPoE support
PPP over Ethernet is a new type of protocol for resolving authentication and billing issues for Ethernet access users. Similar to this is the PPP Over ATM protocol, the router device using this protocol can end access service. The problem of current PPPoE and PPPOA protocol is a capacity problem. Most of the routers that support this protocol can only handle thousands of activities for sessions.
Multicast Support (Enumeration Agreement)
Interconnect Network Group Management Agreement (IGMP)
IGMP (Internet Group Management Protocol) is a member of the IP host to report multi-purpose groups to adjacent multi-purpose routers. Multi-purpose routers are routers that support multicast, send IGMP queries to the local network. The host answers the query by sending an IGMP report. The multicast router is responsible for forwarding the multicast package to the multicast members in all networks.
Distance Vector Multicast Routing Protocol (DVMRP)
DVMRP is a multicast routing protocol based on distance vectors, which is basically based on RIP development. DVMRP uses IGMP and neighbor swap routing packets. Agreement Non-related Multicast Protocol (PIM)
PIM is a multicast transmission protocol that transmits multicast data on existing IP online. PIM is a multicast protocol independent of the routing protocol that works in two modes: intensive mode and loose mode. In PIM dense mode, the packet is defined to all ports until clipping and cutting occurs. In intensive mode assumes that the devices on all ports are multicast members, which may use the multicast package. The loose mode is in contrast to the intensive mode, and only transmits multicast data to the requested port. VPN support
The VPN on the IP has been described in the above router technology. Protocols that may be used include L2TP, GRE, IP Over IP, IPSec, etc. And attention should be paid to the ability to support VPN.
Encryption
The router may use an encryption mechanism in a VPN implementation or otherwise to ensure security. Routers use CPU execution software algorithms usually affect forwarding efficiency. Some routers use hardware encryption in the design to increase forwarding efficiency.
MPLS
MPLS technology has been described in the above router technology. Advanced applications such as fast resection, VPN, traffic engineering in MPLS are included in MPLS. Since the MPLS standard is not yet mature, MPLS is also concerned.
Router performance
Full double line speed forwarding ability
The most basic and most important function of the router is to forward the packet. The forwarding packets at the same port rate are the most testing of the transition capability of the router package. The full-duplex speed forwarding ability refers to two-way transmission on the router port at the router port while the minimum package length (Ethernet 64 bytes, POS port 40 bytes) and the minimum package interval (in accordance with the protocol specification) are not caused by packet loss. This indicator is an important indicator of router performance.
Device throughput
Refers to the device's overall packing ability, which is an important indicator of equipment performance. The work of the router is to route according to the IP header or the MPLS tag, the performance indicator is the number of revolutions per second. The device throughput is usually less than the sum of all port throughput of the router.
Port throughput
Port throughput refers to the transfer of port packets, usually using PPS: packets per second, which is the package transition capability of the router on a certain port. Two identical rate interface tests are usually used. However, the test interface may be related to the location and relationship. For example, the throughput of the end of the card on a card may differ from the port between the ports between the ports on different cards.
Back to back frame
The number of back frames refers to the number of packets that do not cause the maximum packet when the minimum frame interval is not caused. This indicator is used to test router cache capabilities. The router of the wired speed full-duplex forwarding ability This indicator value is unlimited.
Routing capabilities
Routers usually rely on the routing table established and maintained to determine how forward. Routing capabilities refer to the limit of the number of routing items accommodated in the routing table. Since the router that performs BGP protocol on the Internet usually has hundreds of thousands of routing terms, the project is also an important manifestation of router capabilities.
Backplane
The backplane capability is the internal implementation of the router. Backplane capabilities can be embodied in router throughput: backplane capacity is usually greater than the value calculated based on throughput and test package. However, the backplane capability can only be reflected in the design, and it is generally not tested.
Packet loss rate
The packet loss rate refers to the ratio of the number of packets lost in the test, which is typically tested within the throughput range. The packet loss rate is associated with the length of the packet and the package transmission frequency. In some environments, you can add routing jitter, a large number of routing after testing.
Delay
Time delay refers to the time interval of the first bit into the router to the last bit from the router. Test packages are usually used in testing to get test packets to receive the time interval for receiving packets. Time delay is related to the data package length, usually test within the router port throughput, exceeding the throughput test. This indicator is meaningless.
Time slime
Time delay shake is a delay change. Data service is not sensitive to time delay, so this indicator does not appear in the Benchmarking test. Due to the multi-service, including voice, video services, this indicator has the need for testing.
VPN support capabilities
Usually the router can support VPN. Its performance difference is generally reflected in the number of supported VPNs. A dedicated router typically supports a large number of VPNs. No fault working time
This indicator indicates the time when the device has no fault work according to the statistical manner. Generally, it is generally impossible to test, can be calculated by calculating or having a large number of work conditions of the same device.
Internal clock precision
It is usually necessary to synchronize the router interconnects of the ATM port doing circuit simulation or POS ports. If the internal clock is used, its accuracy affects the bit error rate. Internal clock precision level definitions and test methods can be found in the corresponding synchronization criteria. QoS capabilities
Queue management mechanism
Queue management control mechanisms typically refer to the router congestion management mechanism and queue scale algorithm. Common methods include RED, WRED, WRR, DRR, WFQ, WF2Q, etc.
Port hardware queue number
The priority supported in the usual router is guaranteed by the port hardware queue. The priority in each queue is controlled by the queue schedule algorithm. QoS classification
Refers to the information of the router to distinguish between QoS. The simplest QoS classification can be based on port. The same router can also be distinguished from the package priority according to the link layer priority (specified in 802.1q), the upper content (TOS field, source address, destination address, source port, destination port, etc.)
Classification business bandwidth guarantee
Reflect whether the router can guarantee a wide range of business grades. This indicator can be implemented by a queue scheduled algorithm.
RSVP
RSVP is a resource reserved protocol that reserves for resources on end-to-end paths. Using soft status refreshes, it is a flow drive mode. This agreement generally cannot run on a large-scale national network. But usually the router supports the agreement, and some famous vendors use this protocol for MPLS.
IP Diff Serv
Distinguishing service is a simplified QoS to the IP service quality.
Car support
Car is a commitment to the access rate is an access control. Different processes are made of data packets that exceed commitment rates in accordance with the protocols signed with the user: discard or tag; also known as tag color.
redundancy
Redundancy can include interface redundancy, card redundancy, power redundancy, system board redundancy, clock plate redundancy, device redundancy, etc. Redundancy is used to ensure the reliability and availability of the device. The redundancy design should be compromised with the equipment reliability requirements and investment.
Hot plug assembly
Since the router usually requires 24 hours, the replacement component should not affect the router work. The hot swap of the component is the guarantee of the 24-hour router.
Router redundant protocol
The router can guarantee the redundancy of the router via protocols such as VRRP.
network management
The network management means that the network administrator has a centralized management of the network resources over the network management program. Including configuration management, accounting management, performance management, error management, and security management. The network management supported by the device reflects the manageability and maintainability of the device.
Web-based management
Indeed whether the device can manage via the web. It is more convenient to manage by web management, but the security is poor. It is usually allowed to be browsed through web, and it is not allowed to make changes through the web.
Network management type
Indicates the type supported by network management. SNMP protocol management is usually used.
External network management support
Support for external network management indicates whether the router can manage by extracted channels.
Non-mean particle size
Indicates the extent of the router management: manages the port, to the network segment, to the IP address, to the MAC address. Management granularity may affect router forwarding capabilities.
Billing capacity / agreement
As the router enters the operator network, billing is an essential part. The router must be able to support some kind of billing capacity and protocol.
Packet voice ability
Group speech support
In the enterprise, the router packet speech bearing capacity is very important. In remote office and headquarters, the router that supports grouping voice can integrate telephone communication and data communication, effectively saving long-distance calls.
In the current technical environment, the grouping voice can be divided into three types: use IP to carry group voice, use ATM to carry voice and use frame relay voice. Both AAL1 and AAL2 can be divided by using ATM to carry speech. AAL1 is circuit simulation, technology is very mature but relative cost, AAL2 technology is more advanced, but the current ATM interface is usually not supported. The comparative spectacle is relatively mature, relatively low. IP carries the voice currently more popular. The cost is the lowest in the above technique, but the current IP network QoS guarantee is difficult, and the call quality is more difficult.
Protocol support
In the IP carrier voice, H.323 is the ITU standard and is the most common protocol stack of the current IP Phone network. SIP is the IETF standard, its purpose is to simplify network devices and make complex functions into user terminals. From the IP network essential, the router has nothing to do with the loaded business, but the router port supports support for IP Phone protocols. Voice compression
Voice compression is one of the key to the cost of IP telephony. G.723 and G.729 can usually be used. G.723 Recommendation G.723.1 (1996), voice encoder in 5.3 and 6.3kbps multimedia communication transmission dual-rate speech encoder. The relative compression is relatively high, and the compression is delayed. G.729 Recommended in ITU-T G.729 (1996), 8kbps Achieving Digital Excited Line Prediction (CS-ACELP) Voice Coding. The compression is relatively low, and the call quality is better.
Port density
Refers to the ability of the router to support IP phones. Usually calculated in E1, generally an E1 supports 30-channel phone.
Signaling support
Various signaling may be supported on the router E1 port: ISUP, TUP, China No. 1 Signature and DSS1. A router that supports ISUP, TUP or DSS1 signaling can effectively reduce the cycling time. Signaling is usually required in the telecommunication level IP telephone network device. However, as a low-end router, only the DSS1 and China No. 1 signaling are usually supported.
