CCNP Enterprise Core (350-401)
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Quality of Service Models
Quality of Service has three different implementation models. Best Effort Quality of Service is not enabled for traffic in a best effort set-up. Traffic is not given any special or priority treatment. Integrated Services Integrated services leave the responsibility to the application sending the data to signal that special Quality of Service treatment is required.…
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QoS Reasoning: Delay, Latency, and Jitter
Latency is the time it takes for packets to travel across a network from a source to a destination. ITU recommendation G114 recommends that network latency of 400ms should not be exceeded, and real-time traffic latency should be no longer than 150ms. Network latency can be broken down into four categories: Fixed propagation delay Fixed…
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QoS Reasoning: Lack of Bandwidth
Between two destinations, the available bandwidth on a path is equal to the hop with the lowest bandwidth link. If the maximum capacity of this lowest bandwidth link is reached, congestion will take place resulting in traffic drops. The obvious solution is to increase the link bandwidth capacity, but may not always be possible due…
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Quality of Service (QoS)
Quality of Service, or more commonly known as QoS, is a technology that relies on assigning different levels of priority to different types of IP traffic flows. Higher prioritised IP traffic flows are given preference on the network, reducing packet loss on congested links and help control latency plus jitter. Lower prioritised IP traffic are…
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PIM Bootstrap Router: Candidate Rendezvous Points
A PIM bootstrap router that has been configured as a candidate rendezvous point will receive messages from the bootstrap router. The bootstrap router contains information that will identify the current active bootstrap router. The message can be used for the candidate rendezvous point to forward group to rendezvous point mappings from its cache to the…
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PIM Bootstrap Router
The bootstrap mechanism in a PIM router, is a non-proprietary technology providing a fault tolerant, automated rendezvous point discovery and distribution mechanism. The non-proprietary technology is described in RFC 5059 PIM uses the bootstrap router mechanism to discover and announce rendezvous point information for each group prefix to all routers within a PIM domain. The…
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Rendezvous Point Mapping Agents
A Rendezvous Point Mapping Agent joins the multicast group 224.0.1.39 to receive rendezvous point advertisements. When an announcement has been received, it will store it in a group to rendezvous point mapping cache along with a hold timer. If there are multiple of the same group range advertised, the candidate rendezvous points advertisement with the…
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Candidate Rendezvous Point
A rendezvous point configured as a ‘Candidate Rendezvous Point’ or C-RP, advertises via an RP announcement message that it is willing to become a rendezvous point. The candidate rendezvous point advertises this willingness every 60 seconds by default to the multicast address 224.0.1.39. This is controlled by the rendezvous point announce interval. The announcement message…
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Automatic Rendezvous Point
‘Auto-RP’ is a Cisco propriety technology that automates distribution of multicast group to rendezvous point distribution in a PIM topology. Auto-RP has some benefits: Makes it easier to use multi rendezvous points inside of a network to service different group ranges Allows for load splitting across multiple rendezvous points Simplifies rendezvous point placement towards the…
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Static Rendezvous Point
A rendezvous point can be statically configured on a multicast range by configuring the address of the rendezvous point on every router in the multicast domain. This can be the simplest method of configuring a rendezvous point and is suitable for when there are a low number of routers in the network or if the…