IPv4 and IPv6 handle fragmentation differently. IPv4 expects routers to do all of the heavy lifting (fragmentation) while IPv6 moves that responsibility to the sender. The biggest issues we have with IPv4 fragmentation is: 1. it’s costly on our weak router CPUs 2. Any firewalls along the path cannot inspect fragments of an IP packet, …
Category Archives: CCIE R&S
1.1.d (ii) IPv4 options, IPv6 extension headers
IPv4 Options: Within the ipv4 options field there are actually 3 fields: Copy, Option class, and number. The copy section tells us what the packet is for: Datagram and control information Debugging and management information And a reserved field The option class what to do with fragments: Copy the option only into the first fragment …
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1.1.d (i) ICMP Unreachable, Redirect
In this post we will discuss ICMP Type 3 and Type 5 messages as they relate to section 1.1.d (i) Unreachable, Redirect. I have chosen to only go into detail and create flash cards for the important messages. I think they will suffice. The Internet control message protocol (ICMP) has many types of messages and …
1.1.d Explain IP operations
In this section I am going to discuss the IPv4 and IPv6 headers as they relate to the 1.1.d section, explain IP operations. Then we will list out details you should know before proceeding to dive into them in later sub sections. I highly recommend memorizing these fields in the header and I have even …
1.1.d (i) ICMP Unreachables, and Redirects
The Internet control message protocol (ICMP) has many types of messages and codes (sub types). The two discussed below are Type 3 – Destination Unreachable, and Type 5 – Redirect as it relates to 1.1.d (i) ICMP unreachable, redirect. Type 3 – Destination Unreachable: This type of message is sent back to the source …
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1.1.c (iv) Impact of Microbursts
Microbursts are nanoseconds worth of traffic that are so small most monitoring solutions will not see them (they don’t poll often enough). Instead what you may notice is output queue tail drop. This becomes important when discussing how interfaces actually transmit data, on a 1 Gbps interface, a 100 Mbps flow is actually the interface …