# IGMP Snooping **URL:** https://forum.networklessons.com/t/igmp-snooping/1321 **Category:** Lessons Discussion **Created:** [December 29, 2016, 8:38pm UTC](https://forum.networklessons.com/t/igmp-snooping/1321 "2016-12-29T20:38:49Z") **Posts on this page:** 1 **Showing post:** 56
### Author: ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis) #### Post date: [July 17, 2020, 12:53pm UTC](https://forum.networklessons.com/t/igmp-snooping/1321/56 "2020-07-17T12:53:35Z")
Hello Justin What you state makes perfect sense when comparing the MAC address table with the routing table or even more with access lists or route maps. These entities are searched sequentially and when there is a match, the search stops, and action is taken. However, the MAC address table operates differently, and this has to do with the type of memory in which it is stored. Content Addressable Memory (CAM) is type of memory where the MAC address table is stored, and it is also why it is often referred to as the CAM table. Where the previously mentioned entities are searched sequentially line by line, and each line corresponds to a single cycle of the CPU, the CAM table is searched in full in only a single CPU cycle. This is what makes switching so fast. The other characteristic of the CAM table, that actually answers your question, is that **it only makes an exact match**. Only when there is no exact match will it match with the general multicast address group used for IGMP. You can find out more about CAM as well as TCAM memory in the following post: > [@CEF (Cisco Express Forwarding)](https://forum.networklessons.com/t/cef-cisco-express-forwarding/1148/104): > > Hey Gareth This is an interesting question Gareth, and I think you will agree with me that the answer is also very interesting. First of all, let’s take a look at the similarities and differences between CAM and TCAM. What makes both of these memory types fast is the fact that all entries can be searched for in parallel. So if you have hundreds of entries, you can search for a particular value in all the entries in just a single clock cycle. The difference between the two has to do with the… I hope this has been helpful! Laz --- _[View the full topic](https://forum.networklessons.com/t/igmp-snooping/1321)._