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If you're using policy-maps on your Cisco Catalyst switches to handle rate-limiting, you may have noticed that on some models, the show policy-map interface command does not seem to work. The CLI accepts the command and returns properly formatted output, but the output is all zeroes. There is no information …
Posted on in Networking
If you've used Cisco switch clustering in a basic network (for example, when all switches are connected together and <acronym title="Cisco Discovery Protocol">CDP</acronym> is enabled), you've likely never considered how this switches communicate with each other. You might assume that the switches are using IP addresses from …
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The situation: A Cisco 7604 with SAMI card is able to send packets from the individual IOS instances running on the SAMI PPCs, but is unable to receive packets.
The hardware: The table below describes the hardware involved.
| Part Number | Description |
|---|---|
| CISCO7604 | Cisco 7604 Router |
| SUP32-GE-3B | Cisco Catalyst 6500 Series … |
Posted on in Networking
Although routers and switches are often located near each other in a network environment, the two devices offer very different functionality. Routers are network devices that send data packets to distinct network segments. A router examines incoming packets and makes routing decisions based on the destination address in the packet …
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You may already know that the IEEE 802.1D specification recommends a maximum network diameter of 7 hops. What you may not know is that the number 7 is derived from a series of calculations based on various timers being tuned to their default values. If you are designing a …
Posted on in Networking
You'll find that some network problems can only be solved by sticking a packet sniffer on the network and seeing what the packets are doing. In a switched environment, this will not work properly since each port is configured to only broadcast traffic destined for the MAC addresses it has …
Posted on in Networking
<acronym title="UniDirectional Link Detection">UDLD</acronym> is a Cisco protocol designed to detect and disable unidirectional links in Ethernet (fiber or twisted-pair). In the case of a radio-based Metro Ethernet ring, UDLD goes the extra mile in preventing Spanning-Tree loops and user service interruption.
In this simple network of …
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