364 PART III Routing and Routing Protocols 1 byte 1 byte 1 byte 1 byte Next Hop IPv6 Address Must Be All Zeros 32 bits Metric 5 0xFF FIGURE 14.4 The Next Hop in IPv6 with RIPng. Note the use of the special metric value. When the route entry used is an IPv6 Next Hop, the 3 bytes preceding the 0xFF Metric must be set to all 0 bits. This is shown in Figure 14.4. At first it might seem that the amount of the IPv6 routing information sent with RIPng must instantly double in size, since now each 20-byte IPv6 route requires a