Border Gateway Protocol Attributes List - 0 views

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  #1 Archibald Marsh on 17 Sep 12

   

  Table 6-1 describes the effectively-acknowledged and optional characteristics employed in BGP4.
  Table 6-1. Effectively-Known and Optional BGP AttributesAttribute Description
  Origin This attribute is necessary and defines the source of the path and can have 3 different values:
  IGP suggests the remote route originated from in the AS. Usually, when the community command or redistribution is configured, BGP installs the network with an origin set to IGP.
  EBG implies learned via an External Gateway Protocol.
  Incomplete implies the BGP path was learned utilizing redistribution or static routers.
  AS_Route This attribute describes the sequence of autonomous techniques that the packet has traversed.
  Up coming Hop This attribute describes the following hop address taken to a remote route, generally the BGP peer.
  Regional Preference This attribute indicates to the AS the chosen route to exit the AS. A greater regional desire is always chosen.
  MED Multiexit Discriminator informs BGP peers in other autonomous techniques which route to get to a distant network. A reduce MED is usually preferred.
  Excess weight This Cisco-only attribute is utilized in neighborhood router variety. Fat is not sent to other BGP friends, and a higher excess weight value is constantly desired. The fat benefit is in between 0-294967295.
  Atomic This attribute advises BGP routers that aggregation has taken spot and is not utilised in the router-assortment procedure.
  Aggregator This is the router ID dependable for aggregation and is not used in the router-selection method.
  Group Communities allow routes to be tagged for use with a team of routers sharing the same traits.
  Originator ID This attribute is used to stop routing loops. This details is not utilized for router variety.
  Cluster-Listing This attribute is utilised in path-reflector environments. This information is not employed for router assortment.
  
  
  Internal BGP (IBGP) and Exterior BGP (EBGP) are the two types of BGP periods. IBGP is a link amongst two BGP speakers in the very same AS. EBGP is a connection among two BGP speakers in distinct autonomous systems.
  
  Figure 6-one shows a simple 3-router BGP topology and the different BGP link sorts: IBGP and EBGP.
  
  
  Figure six-one and
  
  IBGP friends also make particular that routing loops can not arise by ensuring that any routes sent to yet another AS are identified by means of an inside routing protocol, this sort of as Open up Shortest Path 1st (OSPF), before sending the route details. In other phrases, the routers have to be synchronized. The bonus of this further rule in IBGP TCP periods is that information is not sent until the distant route is reachable, which decreases any unnecessary traffic, and, consequently, saves bandwidth. You can disable this element with the no synchronization command, which is coated afterwards in this chapter.
  
  The BGP routing choice is very complex and normally takes into account the characteristics outlined in Table six-one.
  
  The procedure a Cisco router running BGP4 takes is as follows:
  If the subsequent hop deal with is reachable, think about it.
  Desire the course with the greatest excess weight (Cisco IOS routers only).
  If the excess weight is the very same, choose the largest nearby preference attribute.
  If the local choice is the identical, favor the route this local router originated. BGP Attribute Reference, BGPv4 Attribute Types, Border Gateway Protocol Attribute Types

   

  <div class="cArrow"> </div><div class="cContentInner">Table 6-1 describes the effectively-acknowledged and optional characteristics employed in BGP4.<br />Table 6-1. Effectively-Known and Optional BGP AttributesAttribute Description <br />Origin This attribute is necessary and defines the source of the path and can have 3 different values: <br />IGP suggests the remote route originated from in the AS. Usually, when the community command or redistribution is configured, BGP installs the network with an origin set to IGP.<br />EBG implies learned via an External Gateway Protocol.<br />Incomplete implies the BGP path was learned utilizing redistribution or static routers.<br />AS_Route This attribute describes the sequence of autonomous techniques that the packet has traversed. <br />Up coming Hop This attribute describes the following hop address taken to a remote route, generally the BGP peer. <br />Regional Preference This attribute indicates to the AS the chosen route to exit the AS. A greater regional desire is always chosen. <br />MED Multiexit Discriminator informs BGP peers in other autonomous techniques which route to get to a distant network. A reduce MED is usually preferred. <br />Excess weight This Cisco-only attribute is utilized in neighborhood router variety. Fat is not sent to other BGP friends, and a higher excess weight value is constantly desired. The fat benefit is in between 0-294967295. <br />Atomic This attribute advises BGP routers that aggregation has taken spot and is not utilised in the router-assortment procedure. <br />Aggregator This is the router ID dependable for aggregation and is not used in the router-selection method. <br />Group Communities allow routes to be tagged for use with a team of routers sharing the same traits. <br />Originator ID This attribute is used to stop routing loops. This details is not utilized for router variety. <br />Cluster-Listing This attribute is utilised in path-reflector environments. This information is not employed for router assortment. <br /><br /><br />Internal BGP (IBGP) and Exterior BGP (EBGP) are the two types of BGP periods. IBGP is a link amongst two BGP speakers in the very same AS. EBGP is a connection among two BGP speakers in distinct autonomous systems.<br /><br />Figure 6-one shows a simple 3-router BGP topology and the different BGP link sorts: IBGP and EBGP.<br /> <br /><br />Figure six-one and <br /><br />IBGP friends also make particular that routing loops can not arise by ensuring that any routes sent to yet another AS are identified by means of an inside routing protocol, this sort of as Open up Shortest Path 1st (OSPF), before sending the route details. In other phrases, the routers have to be synchronized. The bonus of this further rule in IBGP TCP periods is that information is not sent until the distant route is reachable, which decreases any unnecessary traffic, and, consequently, saves bandwidth. You can disable this element with the no synchronization command, which is coated afterwards in this chapter.<br /><br />The BGP routing choice is very complex and normally takes into account the characteristics outlined in Table six-one.<br /><br />The procedure a Cisco router running BGP4 takes is as follows:<br /> If the subsequent hop deal with is reachable, think about it. <br /> Desire the course with the greatest excess weight (Cisco IOS routers only). <br /> If the excess weight is the very same, choose the largest nearby preference attribute. <br /> If the local choice is the identical, favor the route this local router originated. <a href="http://www.vilago21.com/event/BGP+Attributes+Reference/1401851/profile" rel="nofollow">BGP Attribute Reference</a>, <a href="http://trentonali12.posterous.com/bgpv4-attributes-reference" rel="nofollow">BGPv4 Attribute Types</a>, <a href="http://ninohess1127.bravejournal.com/entry/110237" rel="nofollow">Border Gateway Protocol Attribute Types</a></div>

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