Ask the Experts: IOS-XR Fundamentals and Architecture

[ciscomoderator]

Welcome to the Cisco Support Community Ask the Expert conversation. 

Learn and ask questions about IOS-XR Fundamentals and Architecture.

November 18, 2014 through November 28, 2014.

Cisco IOS XR Software is a modular and fully distributed network operating system for service provider networks. Cisco IOS XR creates a highly available, highly secure routing platform.

It distributes processes across the control, data, and management planes with their own access controls and delivers routing-system scalability, service isolation, and manageability.

This is a Q&A extension of the Live expert Webcast.

Cisco subject matter experts Sudeep, Raj, and Sudhir, will focus on IOS-XR fundamentals.

Including:-

• High-Level Overview of Cisco IOS XR
• Cisco IOS XR Infrastructure
• Configuration Management
• Cisco IOS XR Monitoring and Operations
• Cisco IOS XR Security
• Introduction to different IOS-XR platforms

Sudeep Valengattil is a customer support engineer in High-Touch Technical Services at Cisco specializing in service provider technologies and platforms. Sudeep has got experience on XR platform like ASR9000, CRS, NCS and GSR. Sudeep has more than 9 years of experience in the IT industry and holds CCIE certification (36098) in Service provider.

Sudhir Kumar is a customer support engineer in High-Touch Technical Services at Cisco specializing in service provider technologies and platforms. His areas of expertise include Cisco CRS, ASR 9K and Cisco XR 12000 Series Routers. Sudhir has more than 10 years of experience in the IT industry and holds CCIE certification (35219) in Service provider and Routing and switching.

Raj Pathak is a customer support engineer in High-Touch Technical Services at Cisco specializing in service provider technologies and platforms. He serves as a support engineer for technical issues supporting Cisco IOS XR Software customers on Cisco CRS and Cisco XR 12000 Series Routers. Raj has more than 8 years of experience in the IT industry and holds CCIE certification (38760) in routing and switching.

For more information about this topic, visit the Expert Corner > Knowledge Sharing

Remember to use the rating system to let the experts know if you have received an adequate response.

 

[Sudeep Valengattil]

Hi Charles,

To answer your question,

LPTS would be acting only on packet/traffic which is ingressing the router and destined for the router itself (for-us packets).  It provides an internal forwarding table to route control/management protocol packets destined to local router to the right application for further processing.  Once we have a packet entering the interface, the network processor would be performing a lookup to determine, if this packet is destined for us.  Based on which, it will forward to LPTS.  For eg, the ICMP packets coming in on an interface with destination IP of router itself, would be processed by LPTS.  It also provides policing function for this traffic transparently.

Key facts about LPTS

1. LPTS is an always on feature.  No user configuration needed to enable it.
2. LPTS is only applicable for traffic entring to the router and destined to the local router. Applies for control-plane and management plane traffic.
3. Packets originated by router and transit traffic is not processed by LPTS
4. LPTS polices the incoming traffic based on the pre-defined policer rates.

Here is an o/p snip to view the LPTS entries.

RP/0/RP0/CPU0:CRS-C#sh lpts pifib hard police loc 0/0/cpu0
Tue Nov 25 23:32:10.666 EDT

-------------------------------------------------------------
                Node 0/0/CPU0:
-------------------------------------------------------------
 Burst = 100ms for all flow types
-------------------------------------------------------------
FlowType               Policer Type    Cur. Rate Def. Rate Accepted   Dropped  
---------------------- ------- ------- --------- --------- ---------- ---------
unconfigured-default   100     Static  500       500       0          0        
L2TPv2-fragment        185     Static  700       700       0          0        
Fragment               106     Static  1000      1000      0          0        
OSPF-mc-known          107     Static  20000     20000     44818      0        
OSPF-mc-default        111     Static  5000      5000      11366      0        

Do let us know if you have any further queries.

Regards,

Sudeep Valengattil