diff --git a/aurp/aurp.go b/aurp/aurp.go
index 3ecca05..1d6022e 100644
--- a/aurp/aurp.go
+++ b/aurp/aurp.go
@@ -4,6 +4,7 @@ package aurp
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 )
@@ -82,17 +83,6 @@ const (
 	CmdCodeTickleAck CmdCode = 0x000f
 )
 
-// CmdSubcode is used to distinguish types of zone request/response.
-type CmdSubcode uint16
-
-// Various subcodes.
-const (
-	CmdSubcodeZoneInfo1         CmdSubcode = 0x0001
-	CmdSubcodeZoneInfo2         CmdSubcode = 0x0002 // only for responses
-	CmdSubcodeGetZonesNet       CmdSubcode = 0x0003
-	CmdSubcodeGetDomainZoneList CmdSubcode = 0x0004
-)
-
 // RoutingFlag is used in the flags field
 type RoutingFlag uint16
 
@@ -218,6 +208,65 @@ func ParsePacket(p []byte) (Packet, error) {
 			rd.Header = h
 			return rd, nil
 
+		case CmdCodeZoneReq:
+			sc, p, err := parseSubcode(p)
+			if err != nil {
+				return nil, err
+			}
+			switch sc {
+			case CmdSubcodeZoneInfoReq:
+				zir, err := parseZIReqPacket(p)
+				if err != nil {
+					return nil, err
+				}
+				zir.Header = h
+				return zir, nil
+
+			case CmdSubcodeGetDomainZoneList:
+				// TODO
+
+			case CmdSubcodeGetZonesNet:
+				// TODO
+
+			default:
+				return nil, fmt.Errorf("unknown subcode %d", sc)
+			}
+
+		case CmdCodeZoneRsp:
+			sc, p, err := parseSubcode(p)
+			if err != nil {
+				return nil, err
+			}
+			switch sc {
+			case CmdSubcodeZoneInfoNonExt, CmdSubcodeZoneInfoExt:
+				zir, err := parseZIRspPacket(p)
+				if err != nil {
+					return nil, err
+				}
+				zir.Header = h
+				zir.Subcode = sc
+				return zir, nil
+
+			case CmdSubcodeGetDomainZoneList:
+				// TODO
+
+			case CmdSubcodeGetZonesNet:
+				// TODO
+
+			default:
+				return nil, fmt.Errorf("unknown subcode %d", sc)
+			}
+
+		case CmdCodeTickle:
+			return &TicklePacket{
+				Header: h,
+			}, nil
+
+		case CmdCodeTickleAck:
+			return &TickleAckPacket{
+				Header: h,
+			}, nil
+
 		default:
 			return nil, fmt.Errorf("unknown routing packet command code %d", h.CommandCode)
 		}
@@ -225,4 +274,6 @@ func ParsePacket(p []byte) (Packet, error) {
 	default:
 		return nil, fmt.Errorf("unsupported domain header packet type %d", dh.PacketType)
 	}
+
+	return nil, errors.New("unimplemented packet handling")
 }
diff --git a/aurp/errors.go b/aurp/errors.go
new file mode 100644
index 0000000..0abda7e
--- /dev/null
+++ b/aurp/errors.go
@@ -0,0 +1,14 @@
+package aurp
+
+type ErrorCode int16
+
+// Various error codes.
+const (
+	ErrCodeNormalClose           ErrorCode = -1
+	ErrCodeRoutingLoop           ErrorCode = -2
+	ErrCodeOutOfSync             ErrorCode = -3
+	ErrCodeOptionNegotiation     ErrorCode = -4
+	ErrCodeInvalidVersion        ErrorCode = -5
+	ErrCodeInsufficientResources ErrorCode = -6
+	ErrCodeAuthentication        ErrorCode = -7
+)
diff --git a/aurp/open.go b/aurp/open.go
index 20e0c3f..1e1b052 100644
--- a/aurp/open.go
+++ b/aurp/open.go
@@ -15,6 +15,9 @@ type OpenReqPacket struct {
 }
 
 func (p *OpenReqPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeOpenReq
+
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(p.Version)
@@ -45,6 +48,9 @@ type OpenRspPacket struct {
 }
 
 func (p *OpenRspPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeOpenRsp
+
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.RateOrErrCode))
diff --git a/aurp/router_down.go b/aurp/router_down.go
index 6cf5fd2..a98b82a 100644
--- a/aurp/router_down.go
+++ b/aurp/router_down.go
@@ -9,10 +9,12 @@ import (
 type RDPacket struct {
 	Header
 
-	ErrorCode int16
+	ErrorCode ErrorCode
 }
 
 func (p *RDPacket) WriteTo(w io.Writer) (int64, error) {
+	p.CommandCode = CmdCodeRD
+
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.write16(uint16(p.ErrorCode))
@@ -24,6 +26,6 @@ func parseRD(p []byte) (*RDPacket, error) {
 		return nil, fmt.Errorf("insufficient input length %d for router down packet", len(p))
 	}
 	return &RDPacket{
-		ErrorCode: int16(binary.BigEndian.Uint16(p[:2])),
+		ErrorCode: ErrorCode(binary.BigEndian.Uint16(p[:2])),
 	}, nil
 }
diff --git a/aurp/route_info.go b/aurp/routing_info.go
similarity index 92%
rename from aurp/route_info.go
rename to aurp/routing_info.go
index 0c9793e..5b71a64 100644
--- a/aurp/route_info.go
+++ b/aurp/routing_info.go
@@ -10,6 +10,12 @@ type RIReqPacket struct {
 	Header
 }
 
+func (p *RIReqPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeRIReq
+	return p.Header.WriteTo(w)
+}
+
 type RIRspPacket struct {
 	Header
 
@@ -17,6 +23,8 @@ type RIRspPacket struct {
 }
 
 func (p *RIRspPacket) WriteTo(w io.Writer) (int64, error) {
+	p.CommandCode = CmdCodeRIRsp
+
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.writeTo(p.Networks)
@@ -37,6 +45,11 @@ type RIAckPacket struct {
 	Header
 }
 
+func (p *RIAckPacket) WriteTo(w io.Writer) (int64, error) {
+	p.CommandCode = CmdCodeRIAck
+	return p.Header.WriteTo(w)
+}
+
 type RIUpdPacket struct {
 	Header
 
@@ -44,6 +57,8 @@ type RIUpdPacket struct {
 }
 
 func (p *RIUpdPacket) WriteTo(w io.Writer) (int64, error) {
+	p.CommandCode = CmdCodeRIUpd
+
 	a := acc(w)
 	a.writeTo(&p.Header)
 	a.writeTo(p.Events)
diff --git a/aurp/tickle.go b/aurp/tickle.go
new file mode 100644
index 0000000..ef3b88b
--- /dev/null
+++ b/aurp/tickle.go
@@ -0,0 +1,25 @@
+package aurp
+
+import "io"
+
+type TicklePacket struct {
+	Header
+}
+
+func (p *TicklePacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeTickle
+	p.Flags = 0
+	return p.Header.WriteTo(w)
+}
+
+type TickleAckPacket struct {
+	Header
+}
+
+func (p *TickleAckPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeTickleAck
+	p.Flags = 0
+	return p.Header.WriteTo(w)
+}
diff --git a/aurp/zone_info.go b/aurp/zone_info.go
new file mode 100644
index 0000000..231a6a9
--- /dev/null
+++ b/aurp/zone_info.go
@@ -0,0 +1,196 @@
+package aurp
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+// CmdSubcode is used to distinguish types of zone request/response.
+type CmdSubcode uint16
+
+// Various subcodes.
+const (
+	CmdSubcodeZoneInfoReq       CmdSubcode = 0x0001
+	CmdSubcodeZoneInfoNonExt    CmdSubcode = 0x0001
+	CmdSubcodeZoneInfoExt       CmdSubcode = 0x0002
+	CmdSubcodeGetZonesNet       CmdSubcode = 0x0003
+	CmdSubcodeGetDomainZoneList CmdSubcode = 0x0004
+)
+
+func parseSubcode(p []byte) (CmdSubcode, []byte, error) {
+	if len(p) < 2 {
+		return 0, p, fmt.Errorf("insufficient input length %d for subcode", len(p))
+	}
+	return CmdSubcode(binary.BigEndian.Uint16(p[:2])), p[2:], nil
+}
+
+type ZIReqPacket struct {
+	Header
+
+	Subcode  CmdSubcode
+	Networks []uint16
+}
+
+func (p *ZIReqPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeZoneReq
+	p.Flags = 0
+	p.Subcode = CmdSubcodeZoneInfoReq
+
+	a := acc(w)
+	a.writeTo(&p.Header)
+	a.write16(uint16(p.Subcode))
+	for _, n := range p.Networks {
+		a.write16(n)
+	}
+	return a.ret()
+}
+
+func parseZIReqPacket(p []byte) (*ZIReqPacket, error) {
+	if len(p)%2 != 0 {
+		return nil, fmt.Errorf("odd number of bytes %d for networks", len(p))
+	}
+	c := len(p) / 2
+	ns := make([]uint16, 0, c)
+	for i := range c {
+		ns[i] = binary.BigEndian.Uint16(p[i*2:][:2])
+	}
+	return &ZIReqPacket{
+		Subcode:  CmdSubcodeZoneInfoReq,
+		Networks: ns,
+	}, nil
+}
+
+// ZIRspPacket represents a ZI-Rsp: a response packet to a ZI-Req.
+//
+// "When the data sender receives a ZI-Req and the zone list for the network or
+// networks for which that ZI-Req requested zone information fits in one ZI-Rsp
+// packet, it sends a nonextended ZI-Rsp."
+// "When the data sender receives a ZI-Req and the zone list for a network about
+// which that ZI-Req requested zone information does not fit in a single ZI-Rsp
+// packet, it sends a sequence of extended ZI-Rsp packets."
+// "All tuples in a single extended ZI-Rsp packet must contain the same network
+// number"
+// "Duplicate zone names never exist in extended ZI-Rsp packets"
+type ZIRspPacket struct {
+	Header
+	Subcode CmdSubcode
+	Zones   ZoneTuples
+}
+
+func (p *ZIRspPacket) WriteTo(w io.Writer) (int64, error) {
+	p.Sequence = 0
+	p.CommandCode = CmdCodeZoneRsp
+	p.Flags = 0
+	// Subcode can vary for this packet type: it's either 1 or 2
+
+	a := acc(w)
+	a.writeTo(&p.Header)
+	a.write16(uint16(p.Subcode))
+	a.writeTo(p.Zones)
+	return a.ret()
+}
+
+func parseZIRspPacket(p []byte) (*ZIRspPacket, error) {
+	zs, err := parseZoneTuples(p)
+	if err != nil {
+		return nil, err
+	}
+	return &ZIRspPacket{
+		// Subcode needs to be provided by layer above
+		Zones: zs,
+	}, nil
+}
+
+type ZoneTuples []ZoneTuple
+
+type ZoneTuple struct {
+	Network uint16
+	Name    string
+}
+
+func (zs ZoneTuples) WriteTo(w io.Writer) (int64, error) {
+	if len(zs) > 65535 {
+		return 0, fmt.Errorf("too many zone tuples [%d > 65535]", len(zs))
+	}
+	for _, zt := range zs {
+		if len(zt.Name) > 127 {
+			return 0, fmt.Errorf("zone name %q too long", zt.Name)
+		}
+	}
+
+	a := acc(w)
+	a.write16(uint16(len(zs)))
+	offsets := make(map[string]uint16)
+
+	for _, zt := range zs {
+		a.write16(zt.Network)
+
+		if offset, wrote := offsets[zt.Name]; wrote {
+			// Optimised tuple
+			a.write16(0x8000 | offset)
+			continue
+		}
+		// Long tuple
+		offsets[zt.Name] = uint16(a.n - 4) // 4 = sizeof(zone count) + sizeof(first network number)
+		a.write8(uint8(len(zt.Name)))
+		a.write([]byte(zt.Name))
+	}
+
+	return a.ret()
+}
+
+func parseZoneTuples(p []byte) (ZoneTuples, error) {
+	if len(p) < 2 {
+		return nil, fmt.Errorf("insufficient input length %d for zone tuples", len(p))
+	}
+	count := binary.BigEndian.Uint16(p[:2])
+	p = p[2:]
+
+	if len(p) < int(3*count) {
+		return nil, fmt.Errorf("insufficient remaining input length %d for %d zone tuples", len(p), count)
+	}
+
+	zs := make(ZoneTuples, 0, count)
+	var fromFirst []byte
+	for range count {
+		if len(p) < 3 {
+			return nil, fmt.Errorf("insufficient remaining input length %d for another zone tuple", len(p))
+		}
+		var zt ZoneTuple
+		zt.Network = binary.BigEndian.Uint16(p[:2])
+		p = p[2:]
+		if nameLen := p[0]; nameLen&0x80 == 0 {
+			// Long tuple
+			if fromFirst == nil {
+				fromFirst = p
+			}
+			p = p[1:]
+			if len(p) < int(nameLen) {
+				return nil, fmt.Errorf("insufficient remaining input length %d for zone name of length %d", len(p), nameLen)
+			}
+			zt.Name = string(p[:nameLen])
+			p = p[nameLen:]
+		} else {
+			// Optimised tuple
+			if len(p) < 2 {
+				return nil, fmt.Errorf("insufficient remaining input length %d for offset", len(p))
+			}
+			offset := binary.BigEndian.Uint16(p[:2])
+			offset &^= 0x8000
+			p = p[2:]
+			if int(offset) >= len(fromFirst) {
+				return nil, fmt.Errorf("optimized zone tuple offset %d out of range", offset)
+			}
+			nameLen := fromFirst[offset]
+			if len(fromFirst) < int(nameLen) {
+				return nil, fmt.Errorf("insufficient remaining input length %d for zone name of length %d", len(p), nameLen)
+			}
+			zt.Name = string(fromFirst[offset+1:][:nameLen])
+		}
+
+		zs = append(zs, zt)
+	}
+	return zs, nil
+}