struct Node {
...
    NetworkData networkData;
...
};

struct NetworkData {
    NetworkDataIp* networkVar;
...
};

struct NetworkDataIp {
...
     NetworkForwardingTable forwardTable;
...
};

typedef struct {
    int size;
    int allocatedSize;
    NetworkForwardingTableRow *row;
} NetworkForwardingTable;

typedef struct {
    NodeAddress destAddress;
    NodeAddress destAddressMask;
    int interfaceIndex;
    NodeAddress nextHopAddress;
    int cost;
    NetworkRoutingProtocolType protocolType;
    NetworkRoutingAdminDistanceType adminDistance;
    BOOL interfaceIsEnabled;
} NetworkForwardingTableRow;

NetworkPrintForwardingTable(Node *node) {
    NetworkDataIp *ip = (NetworkDataIp *) node->networkData.networkVar;
    NetworkForwardingTable *rt = &ip->forwardTable;
...
    for (i = 0; i < rt->size; i++) {
        char address[20];
        IO_ConvertIpAddressToString(rt->row[i].destAddress, address);
        IO_ConvertIpAddressToString(rt->row[i].destAddressMask, address);
        printf("%5u", rt->row[i].interfaceIndex);
        IO_ConvertIpAddressToString(rt->row[i].nextHopAddress, address);
        printf("%5u      ", rt->row[i].protocolType);
...