How apt enhance the stability of the web laye

The fast evolution of broadband services to traditional telecom and IT industry has brought profound changes. Multi-service, multi-network assembly has transform one irreversible trend. Broadband MAN MAN with the main web as an entity ambition be 3G, NGN and additional new value-added services bearing platform. 3G, NGN such real-time voice and video applications necessitate Metro to provide quality of service similar to traditional telecommunications technology and 99.999% carrier-class network reliability requirements. Meanwhile, ferocious competition will drive the conveyor to provide buyers with a quality of service similar to SLA service guarantees, web stability is one of the first and maximum important indicator. By improving the reliability of the network, operators can offer told services, in tournament between carriers occupies a favorable location to beyond create and consolidate the corporate brand picture.

MAN router reliability is reflected in the following two appearances, one is the reliability of the device layer, variant layer of network reliability.

MAN router network reliability is an important factor of reliability, security, deserving to the traditional router slow convergence protocol (IGP by the second level, BGP level in minutes), can not meet the needs of carrying real-time business. Network reliability is the metro routers are vigorous zones of new technology.

the current reliability of the emerging network-layer IP routing technology, have quickly convergence, end to end backup LSP, MPLS Fast Reroute, graceful restart, RPRIPS and so on.

IP routing fast convergence

IP dynamic routing is the basic reliability of the network layer security mechanism is the inherent feature of IP routing network. IP dynamic routing protocol is responsible for network layer IP forwarding path enumeration,Christian Louboutin Mary Janes, the link or knot failure, leading to the elemental file forwarding path is disturbed, the data forwarding path routing protocol for dynamic re-calculation, however a variety of routing protocols by using different mechanisms, The rejoinder time inconsistency, but the average level in the second level. Traditional IP services for this recovery time is acceptable, but for carrying real-time services such as multi-service carrier-class IP network is required to restore millisecond feedback time, the traditional IP routing technology and the dynamic requirements of a huge breach.

in the traditional routing protocols, based on the promotion of IP routing protocols can reduce the response time of the failure of these measures is primarily to accelerate the convergence of routing protocols. Speed ​​up the convergence rate routing protocols can be divided into link failure detection, routing re-calculation, routing information updates, and several other considerations. By accelerating the link Hello messages sent between the frequency, speed and speed up the SPF calculation for the routing update information set tall precedence, routing protocols can quickly ascertain the fault, and routed quickly and accurately updated, to speed up the convergence of routing protocols, By optimizing the IGP routing protocol convergence can be achieved is fewer than 1s.

Another direction to more and more the convergence of routing protocols IGP and EGP is used for a reasonable level of network maneuvering, IGP for routing within the device, EGP (BGP4) carrying outer route,Christian Louboutin High Heels, the two routes between the effective solitude, not with each other re-distribution. IGP and BGP logical department of fatigue, forming a hierarchical routing framework, intra-and inter-domain routing protocol convergence are independent of each other, can achieve the fastest speed of convergence.

LSP protection switching

protection switching is the term used by ITU-T, MPLS protection switching techniques as improving network availability and permanence is fussy. Protection switching generally protected LSP routes precomputed and pre-allocation of resources, so you can assure that LSP connection failure alternatively interruption of network resources can be rapidly regained.

current technology can merely assist point to point LSP protection switching, protection can be accustomed in 2 ways: 1 +1 protection and 1:1 protection.

1 +1 protection using a devoted backup LSP LSP as the primary protection in IngressLSR at the primary LSP and backup LSP bridge together, the main traffic on the LSP to a backup LSP at the same time sent to the EgressLSR,Christian Louboutin Flats, EgressLSR along to fault indication parameter amount, choose to receive traffic on the standby LSP.

1:1 dedicated protection is likewise used as the basic backup LSP LSP protection, but the standby LSP is not simultaneously bring the same traffic, the backup LSP LSP is going in the main premise can bring other traffic flow protection switching decision in IngressLSR for.


MPLS Fast Reroute (FRR)

order to meet such for movie conferencing, real-time television this class of business applications, these streams have to be invested alike to traditional SDHAPS millisecond LSP protection.

LSP protection switching technology, the signaling protocol required the intervention of the point of failure to reinstate the whistling semaphoring migrate point of the fault indication introduces needless network retrieval delay. MPLS Fast Reroute technology can achieve in the deficiency of whistling semaphoring comprised in the case, the mistake detection point directly to the failure correlate vehicle based aboard pre-set way to redirect the protection, revitalization point is the point of failure. Most of the rapid re-routing contrive depends aboard pre-established export outlet while the network detects a network failure revitalization point, it absences to be done is to simply update the LSP switching table,Christian Louboutin Boots, so that the LSP vehicle from the failed port switches to pre-establish the regular wharf among the LSP.

counting to the avails of fast reroute protection can mushroom the speed of recovery, but via selective feeble link in the network configuration protection, to lest repetition in the authentic network protection, unnecessary consumption of the core network resources. MPLS Fast Reroute technology to provide protection switching within 50ms, as SDHAPS choice protection mechanisms.

MPLS Fast Reroute using the following configuration:

First, the entry to the LSP that LSR1, using a user directive to activate MPLS protection switching function; LSR1 LSP path to send all the LSR send signaling, are calculated for each LSR afterward hop LSR bypass a backup LSP, LSP Fast Reroute configuration is complete. When the LSP path to a downstream LSR detects a failure, by the LSR flow locally within the switch to the backup LSP.

in the IETF in a variety of fast re-routing adoptions, the two main ways to protect the link protection and node protection, their fancies and solve problems of different complexity,Christian Louboutin UK, the technology currently there is no official the RFC.

graceful restart (Gracefulrestart)

control airplane restart may be caused by ingredients including: software updates, software Bug or hardware failure, reboot can be done without interruption control plane restart, the data aircraft without interruption forward. However, if the control plane failure,Christian Louboutin Discount, on the other routers will recalculate the route, bypassing the router failure, non-stop data forwarding plane does not make sense, and the failure route will scatter to the entire network range. In MPLSVPNPE router If this happens, the outcome is ruinous.

graceful restart control plane technology can effectively solve this problem, using the technology in the router control plane fails, you can advise adjoining routers to persist to use the original path data forwarding, and reboot the router and adjoining routers to re-establish routing state to ensure service availability in the restart process, a unattached device to reduce the shock of restarting the entire network.

graceful restart process in the router does not save the agreement narrated to the state, so the cause of software failures will not continue to restart after the restart.

graceful restart is a fashionable feature, a lot of antique equipment can no support it in the local subnet can support the features of the apparatus.

the network border, the siteline router operators face a number of customers, and generally are not needless amounts, the most suitable technology to use graceful restart. Core network is generally used to defend redundant paths, and restart with the business likely to reason a routing circulate, so I do not suggest the use of graceful restart in the essence network technology.