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Cisco: Jabber Video for TelePresence

Apr.3.2012 4g1vn

Experience telepresence with your family/friends/coworkers. Try our free Jabber Video client today. HD video camera recommended. https://www.ciscojabbervideo.com/home http://www.cisco.com/en/US/prod/collateral/ps7060/ps11303/ps11310/ps11328/data_sheet_c78-628609.html Jabber Video system requirements Windows Windows 7, Vista, or XP (SP 2 or newer), with: • OpenGL 1.2 or newer • For 720p HD calls, Intel Core2Duo @ 1.2 GHz or better • For VGA calls, Intel Atom @ 1.6 GHz or better Webcam (built-in or external; you’ll need an HD webcam for the other side to see you in HD) Broadband…

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CCIE: QoS

Mar.25.2012 4g1vn

Hold-Queue & Hardware TX Ring: TX-Ring DEFAULT on 1841 (128) packets on a FastEthernet interface “tx-ring-limit X” verify with “sh controller fa 0/1 | in tx” FIFO Ingress queue is 75 packets by default and 40 packets on an 1841 FastEthernet interface “hold-queue X in|out” verify with “sh interface fa0/1 | in queue” Keep in mind that the software queue is only invoked when the hardware (TX-RING/FIFO) is full. CPU/packet spikes can tie up CPU cycles causing the router to use…

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CCIE: Multicast

Mar.18.2012 4g1vn

Preface: To clear old entries in the multicast table, use “clear ip mroute *”. This command usually will allow changes to be sync:ed, but not always. In the worst case scenario, you may have to reload the device. Modifications to a working multicast environment is not recommended if you cannot interrupt traffic forwarding. Be sure to schedule maintenance window in a REAL production environment. PIM: Signaling protocol that uses the unicast routing table to preform RPF checks. Dense mode: Flood to all multicast enabled interfaces and downstream routers prune…

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CCIE: MPLS

Mar.15.2012 4g1vn

MPLS: Autoconfig (enable LDP on all interfaces) only available when using OSPF as IGP. LDP send discovery packets via UDP to 224.0.0.2 (all routers) port 646. Route-ID is highest loopback but can be forced “mpls ldp route-id x.x.x.x force”. To use the physical connection of the interface (not the loopback due to lack of reachability) use this command on the interface. ” mpls ldp discovery transport-address interface”. Once communications is established, via TCP 646, authentication is verified (MD5 only). After peer is…

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New Edition to my Neo Collection!

Mar.3.2012 4g1vn

Not sure if anyone really cares, but I’m a huge NeoGeo fan/collector.. Today I found quite a surprise at a local gaming store. English version of SvC Chaos (SNK vs. Capcom) for the NeoGeo AES. Needless to say, I did not even hesitate for a second and bought it. It’s in pristine condition and I’ll probably spend the rest of the night obsessing on how beautiful the condition is. Enjoy these pics and Thank You Play N Trade! Game Data: …

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CCIE: BGP

Feb.18.2012 4g1vn

Unlink IGP’s, BGP does not use metrics to select best path. Instead, BGP is vector based. This path is determined with Path Attributes (PA’s). The default PA, if no others are set is AS-PATH. Shortest path to destination prefix is the best path. Building the neighbor relationship: TCP Port 179 (established based on neighbor address), Open, Established, and finally Updates (contains the prefix information). If there is a problem/error a “notification” message is sent. Keepalive is 60 and hold time is…

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CCIE: RIP

Feb.14.2012 4g1vn

Notes: auto-summary in RIP affects what is advertised, but not the local RIB. Preventing route feedback: Prevent router feedback (RIP) with static route to null0 or distribute-list (IN) on originating router. interface> ip rip advertise (interval different than the global) default sent out specific interface: use route-map that sets interface and default-information originate. DON’T FORGET ABOUT ROUTE FEEDBACK IN RIP! ACL to filter even/odd octets: ip access permit 0.0.1.0 255.255.254.255 : permit 3rd octet odd only ip access permit 0.0.0.0 255.255.254.255…

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CCIE: GRE Tunneling/Recursive Routing

Feb.12.2012 4g1vn

Here is a subject and burned me in my last lab. I had a much more complex environment, but the fundamentals are the same. Recursive routing errors occur when the tunnel destination is dynamically learned across the tunnel interface itself. Here are two simple methods to correct this behaivor. 1) Static route to the tunnel destination via any interface/path, but the tunnel interface (lower metric then a dynamic learned IGP). On the CCIE lab static routes are generally a no-no, that being…

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CCIE: OSPF

Feb.4.2012 4g1vn

The Basics: Link state routing protocol. Uses IP protocol 89. Hellos sent on 224.0.0.5. Uses Dijkstra SPF algorithm independently on each router against the local LSDB to calculate the best routes. Hellos sent every 10 seconds on LAN and 30 seconds on WAN interfaces. Dead time is 4x hello, so 40sec and 120 sec respectively. Router ID: 1) Configured “router id” 2) Highest loopback 3) Highest non loopback interface in up/up state. Hello Process Sanity check: Pass authentication (verify with “debug ip ospf adj”)…

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