Limiting The Number Of Hops An Ipv6 Packet Can Traverse - Brocade Communications Systems ICX 7250 Series Configuration Manual

Limiting the number of hops an IPv6 packet can traverse

Limiting the number of hops an IPv6 packet can
traverse
By default, the maximum number of hops an IPv6 packet can traverse is 64. You can change this value to between 0 - 255 hops. For
example, to change the maximum number of hops to 70, enter the following command.
device(config)#ipv6 hop-limit 70
Syntax: [no] ipv6 hop-limit number
Use the no form of the command to restore the default value.
hop-limit 0 will transmit packets with default (64) hop limit.
number can be from 0 - 255.
IPv6 source routing security enhancements
The IPv6 specification (RFC 2460) specifies support for IPv6 source-routed packets using a type 0 Routing extension header, requiring
device and host to process the type 0 routing extension header. However, this requirement may leave a network open to a DoS attack.
A security enhancement disables sending IPv6 source-routed packets to IPv6 devices. (This enhancement conforms to RFC 5095.)
By default, when the router drops a source-routed packet, it sends an ICMP Parameter Problem (type 4), Header Error (code 0) message
to the packet's source address, pointing to the unrecognized routing type. To disable these ICMP error messages, enter the following
command:
device(config)# no ipv6 icmp source-route
Syntax: [no] ipv6 icmp source-route
Use the ipv6 icmp source-route form of the command to enable the ICMP error messages.
TCAM space configuration
Brocade devices store routing information for IPv4 and IPv6 routing and GRE tunnel information in the same ternary content-
addressable memory (TCAM) table. You can configure the amount of TCAM space to allocate for IPv4 routing information and GRE
tunnels. The remaining space is allocated automatically for IPv6 routing information.
Brocade devices vary in the amount of TCAM space that can be allocated for IPv4 and IPv6 routing and GRE tunnel information. Each
IPv6 route entry and GRE tunnel use more storage space then IPv4 route entries. The default, maximum, and minimum allocation values
for each type of data are shown in the following tables.
NOTE
If you disable IPv6 routing, the TCAM space allocations do not change. If you want to allocate the maximum possible space for
IPv4 routing information, you must configure the TCAM space manually.
TABLE 28 TCAM space allocation on ICX 7750 devices
IPv4 route entries
IPv6 route entries
158
Default
12000
5120
Maximum
15168
5120
Brocade FastIron Layer 3 Routing Configuration Guide
Minimum
4096
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