Cisco ACI APIC hardware Migration from M1 to M3
There are two ways to migrate APIC M1 to M3 Option 1: This is a more detailed migration guide Similar to replacing a faulty APIC:...
View ArticleConverged Stack comparison
Q: Why Cisco has so many converged stacks, and which one should I choose? Converged stacks can help reduce the overall cost of deploying and managing IT infrastructure and provide an alternative for...
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SDA: a deep dive into the custom ASIC: UADP 2.0 and QFP
Q: What is special about the custom ASIC in the Cisco Catalyst 9000 switch? In brief, UADP 2.0 ASIC in Catalyst 9K is field-reprogrammable, which means we can deliver new features without upgrading the...
View ArticleSDA: Software Define Access
This is a really nice write-up to break down the SDA concept:http://datanetworkingtalk.com/cisco-sda-moving-software-defined-to-the-access-layer/
View ArticleIS-IS notes
1. ATT bit A Level 1/Level 2 router that is attached to another area will set the "attached bit" in its Level 1 LSP; all the Level 1 ISs in an area will get a copy of this LSP and know where to forward...
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OSPF notes
why two router will get stuck at two-way state?Sometimes it is desirable for a router to be configured so that it is not eligible to become the DR or BDR. You can do this by setting the OSPF priority...
View ArticleCEF
cef load balancingThe adjacency table is populated as adjacencies are discovered. Each time an adjacency entry is created (such as through the ARP protocol), a link-layer header for that adjacent node...
View ArticlePfR
three factors PfR used to calculate the best exit path:Passive monitoring metrics include the following:• Delay: Cisco PfR measures the average delay of TCP flows for a given prefix or traffic class....
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security
CHAPChallengeFigure 3 – A CHAP Challenge Packet is BuiltFigure 3 illustrates these steps in the CHAP authentication between the two routers:A CHAP challenge packet is built with these...
View ArticleDMVPN
QOS issues: use qos pre-classify or associate a NHRP GRoup to a QoS policyhttp://www.cisco.com/c/en/us/support/docs/quality-of-service-qos/qos-policing/10106-qos-tunnel.html#qoscommThe qos pre-classify...
View Articleimprovements of IOS XE over IOS
http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-xe-3sg/QA_C67-622903.htmlMulti-Core CPUs and SMPRunning IOS and other applications as separate processes also enables load...
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MPLS
With Route Target Constraint (RTC), the RR sends only wanted VPN4/6 prefixes to the PE. 'Wanted' means that the PE has VRF importing the specific prefixes.RFC 4684 specifies RTC. The support is through...
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BGP notes
1. requirements for BGP to install a classful network into BGP routing table:When a subnet exists in the routing table and these three conditions are satisfied, then any subnet of that classfull...
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DHCP
client identifiersThis command is used for DHCP requests.•DHCP clients require client identifiers. The unique identification of the client is specified in dotted hexadecimal notation, for example,...
View ArticleEIGRP
limit the range of EIGRP queries:1.summarize routes at the boundary routers2.Stub routers in EIGRP domain===In a hub and spoke topology, the remote router must forward all nonlocal traffic to a...
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SSHv2
Restrictions for Secure Shell Version 2 Support•SSH servers and SSH clients are supported in 3DES software images.•Execution Shell, remote command execution, and SCP are the only applications...
View Articlespanning-tree notes
1. Mitigate unicast packet flooding: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/23563-143.html Ports with the STP portfast feature enabled will not cause TCNs...
View Articlespanning-tree notes
1. Mitigate unicast packet flooding: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/23563-143.html Ports with the STP portfast feature enabled will not cause TCNs...
View Articlespanning-tree notes
1. Mitigate unicast packet flooding: http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6000-series-switches/23563-143.html Ports with the STP portfast feature enabled will not cause TCNs...
View Articlemulticast notes
MLD:Multicast Listener Discovery The protocol is embedded in ICMPv6 instead of using a separate protocol. MLDv1 is similar to IGMPv2 and MLDv2 similar to IGMPv3. Code session in MLC message is...
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